Set Display in a Lookup field to a field in another form which is itself a lookup field

Set Display in a Lookup field to a field in another form which is itself a lookup field

Is it possible to set Display in a Lookup field to a field in another form which is itself a lookup field? 

Say I am setting the lookup field to connect to the auto index number in another form since it is unique but I want the user to see a combination of a Customer Name + Lot Number since that make more sense for him.

How do I do this. Any ideas?