I'm wanting to create an item counter, based upon current records. Case in point: I want all records that are tied to a certain work order # to "count" so that when I push new record it will put the appropriate number.

WO# 1010
Item 1:
Item 2:
Item 3:

Then, if I push "New Record", it will automatically put #4 in the item number box. See what I'm asking for?