Steve,

You can't use FormFieldValue (there's no form) but you can "filter" the subrecords.

If your subreport has these three elements: TransactionType, Item, PurchasePrice

Try something like this in the On Print event for the first element to show only Sale transactions:

If (TransactionType = "SALE")
{
       Visibility(TransactionType, 1)
       Visibility(Item, 1)
       Visibility(PurchasePrice, 1)
}
Else
{
       Visibility(TransactionType, 0)
       Visibility(Item, 0)
       Visibility(PurchasePrice, 0)
}

If you are doing summaries (like totals), you will need to maintain your own values in variables. Summary Elements will not automatically skip the invisible rows.

Give it a try and let us know how it works out for you.