Wow... maintaining real-time accuracy of something like that will be practically impossible (as orders are created / edited / shipped). 

Why not just query the value whenever you need it?

Thanks for the quick reply. Its just to help our CS team know how many orders an item is on.

The orders are listed on that screen... is that not sufficient?

If your script comes up with the right count, why not just do a pop-up message with the value (instead of writing to a UDF)?

They want the count for each in separate fields. Any other suggestions? I don't think the script idea will work.

If they want accurate counts in separate fields, you're looking at expensive custom programming.

A button script ODBC query / pop-up with the values seems feasible.