Purchase Order Entry Vantage 8.03

When creating a PO, on the line tab, entering data to purchase a part for a Job: Any ideas/tricks on limiting the assembly drop down list?

We have the same subassembly under different assemblies.
ASM 1 = 52500
ASM 3 = 0040
ASM 2 = 52510
ASM 4 = 0040

When looking at the drop down list, you see all four assemblies.
Ideal fix would be to concatenate the child to the parent, if it exists.
The list would look like:
52500-0040
52510-0040
and the assemblyseq would the be lowest level (ASM 3 and 4).

Any assistance would be appreciated
Clinton