As I am aware of, it is not possible to use the trim tool in weldement on bodies that is not structural members.(witch I feel is a lack of functionality in the weld module)
And I can not find any boolean tools that can do this either. The option I'm after is similar to cavity (mold tools) but this function is only
available in assembly mode. Is my observations correct? And must I really make a corresponding sketch, or extract surfaces from the othe body to do this cut?