Adjustable part does not work.

Can a part file with multiple bodies in it be used as an adjustable part in an assembly?

You can only have one body active at a time in a part file with multiple bodies. If you do not choose to publish them into individual files, then the only other option is to Right Mouse click on the body you want active in the assembly and set it to "Activate Assembly Body". Either way, because of this rule, you will not be able to use Adjustable Part with a multi-body part file in an assembly. Notes