Is there a way to stop wtparts being created by auto-associate based on name of the CAD document?

When we create designs of plastic injection moulded parts we model it as an assembly which contains the actual plastic part plus any inserts and/or paint with a naming convention similar to the image below

Using the example above, auto-associate creates wtparts for MP123456.asm, MP123456_moulding.prt and the BP parts. We don't really need the wtpart for MP123456_moulding.prt. Is there a way to stop auto-associate from creating this wtpart using, for example the fact the number (mp123456_moulding.prt) contains an underscore or could an attribute be used to tell auto-associate not to create the wtpart?

Thanks in advance.

David.