If I use private data session (changing an existing application) can I do the following (if so how).

Form A is used to issue stock items. It checks if stock is availble by looking in the inventory table.
Occationally Inventory table is incorrect (i.e. not updated with recieved items yet). In that case user opens form B
to update the quantity on hand field, closes Form B, returns to Form A and continues with order. There are some
glitches that others have suggest would be fixed if I used private data sessions. If I understand what has been
said about private data sessions form A will NOT see changes made by form B.

Can I some how still use private data sessions and still have changes in inventory table
be seen by Form A so it knows that there are really enought items in stock to complete the order?