I would like to create a property based on which part is inserted.

In these days I'm working in this way:

1) I take the semifinished product I need

2) I make some sketch which will dictate limits and "guidelines" to the real model

3) I make final sketch and their derived features

Sometimes new products are the same only with bigger size, so that I can do all the work just by changing the semifinished piece they are based on.

So I would like to create a property based on which part is inserted; in this way the title block would always be updated with the correct semifinished product, without needing manual intervention.