My Purchase Order code posts a changed cost from PO!ItemCost into Inventory!ItemCost (using the code below).  But the next step I'm having a little trouble with conceptualization. 

In my Pricing database, I may have 100 records representing the price of a particular item for 100 different clients (one client gets a 12% margin, another gets a 20% margin and so on).  What I want is for a new price to be automatically calculated and posted into each Pricing record whenever there is a cost change to that ItemNum, as determined when the PO!ItemNum is placed and the new cost recorded (Item was $30.00, and now it's $31.00). 

At the moment the PO line item cost is recorded, I want the code to go look in my Pricing database for all records of that ItemNum, and automatically update all of those records to new pricing, based upon the specific margin in each Pricing record.

I need to get a result set of all Pricing records for that ItemNum, post the new cost in the Pricing!ItemCost field, then pull the Pricing!Margin value and use ItemCost/(1-Margin) to get a new Price Value, which is then posted into the Pricing!ItemPrice field, then go to the next record and repeat the process.
     So I think I need to get the result set, then loop through it one record at a time, performing the pull/calc/post on each record, then remove that record from the set, then repeat the process on the next record, and so on.  Correct?   If so, Can someone get me started on setting up the loop code in conjunction with the XResultSet Search and SetValue ?  Many thanks. 

#include "sbasic_include.sbas"
//this group of var's is for XResultSet to get Inventory current fields to post to Inventory Last fields
var vLastCost as money
var vLastPOQty as double
var vLastPOAvail as string
var vLastPONum as string
var vLastPODate as date
var vLastVendor as string

//this group of var's is for XResultSet to post data to Inventory record
var vRS as Int
var vItemCCost as Money
var vItemqQty as double
var vItemAvail as string
var vPONum as string
var vPODate as date
var vVendor as string

// this group is for the writing of line items ordered to the SummaryView MultiLine field
var vTemp as Int
var vLine as String
var vItemNum as String
var vItemQty as String
var vItemUoM as String
var vItemDesc as String
var vSumView as String
var vSumView1 as String

vItemNum = ItemNum
vItemQty = ItemQty
vItemUoM = ItemUoM
vItemDesc = ItemDesc


    If ((@Mode() = 1) or (@Mode() = 0)) and (@isBlank(POLinesYN) = 0)
     {
           // this XResult section below posts line item data to Inventory record
           vRS = @XResultSetSearch(@FN, "Inventory", SEARCH_MODE_AND,SEARCH_SYNTAX_QA, "!ItemNum=" + @Str(ItemNum))
           If vRS > -1
           {
                 //Confirm exactly one matching record
                 If @XResultSetTotal(vRS) = 1
                 {
                       //Confirm I can change the Inventory record
                       If @XResultSetLocked(vRS) = 0
                       {
                       //   Get the current field info in Inventory in order to post it to the 'Last' fields in Inventory
                             vLastCost = @XResultSetValue(vRS, "ItemCurrentCost")
                             vLastPOQty = @XResultSetValue(vRS, "CurrentPOQty")
                             vLastPOAvail = @XResultSetValue(vRS, "CurrentPOAvail")
                             vLastPONum = @XResultSetValue(vRS, "CurrentPONum")
                             vLastPODate = @XResultSetValue(vRS, "CurrentPODate")
                             vLastVendor = @XResultSetValue(vRS, "CurrentVendor")
                       //   Get the current relevant field info from POLines to post in Current fields in Inventory
                             vItemCCost = ItemCost
                             vItemqQty = ItemQty
                             vItemAvail = ItemAvail
                             vPONum = PONum
                             vPODate = @FormFieldValue("Purch", "PODate", 0)
                             vVendor = @FormFieldvalue("Purch", "VendorID", 0)
                             
                       // Post/Set the existing PO data in Inventory from 'current' to 'last'
                             XResultSetValue(vRS, "LastCost", vLastCost)
                             XResultSetValue(vRS, "LastPOQty", vLastPOQty)
                             XResultSetValue(vRS, "LastPOAvail", vLastPOAvail)
                             XResultSetValue(vRS, "LastPONum", vLastPONum)
                             XResultSetValue(vRS, "LastPODate", vLastPODate)
                             XResultSetValue(vRS, "LastVendor", vLastVendor)

                       // Post/Set the data in POLines to the 'current' data fields in Inventory
                             XResultSetValue(vRS, "ItemCurrentCost", vItemCCost)
                             XResultSetValue(vRS, "CurrentPOQty", vItemqQty)
                             XResultSetValue(vRS, "CurrentPOAvail", vItemAvail)
                             XResultSetValue(vRS, "CurrentPONum", vPONum)
                             XResultSetValue(vRS, "CurrentPODate", vPODate)
                             XResultSetValue(vRS, "CurrentVendor", vVendor)
                       }
                       Else
                       {
                             @MsgBox("Error: Inventory record is locked by another user.","","")
                       }
                 }
                 Else
                 {
                       @MsgBox("Error: There must be only one matching Inventory record.", "", "")
                 }
                 XResultSetClose(vRS)      //Close the result set
                 vLine = vItemNum + " ** " +  vItemQty + " " + vItemUoM + " ** " +  vItemDesc + @Newline() + "==========" + @Newline()
                 POLstr = vLine
                 QtyStillDue = ItemQty - QtyRecd0
                 @Save
                 If @isBlank(ItemNum)
                       {
                             ThrowFocus(ItemNum)
                       }
                       else
                       {
                             ThrowFocus(ItemCost)
                       }
           }
           Else
           {
                 @MsgBox("Error: Cannot open XResultSet.", "", "")
           }

     }