Am I right in understanding that there's no Evaluation Option to check the interference in a Part? It's possible for assemblies, so why not multibody parts?
I just found this strange when I went to check there so it would be nice if someone could tell me why.
Another option you may want to consider is as follows:
Create a new temporary assembly
Place multi-body part files in assembly
Run Interference Detection and check the Option box for: Include multibody part interferences