fasten mate

I've tried several things here and can't quite get what I want. I have a lot of parts within a Parts Studio drawn exactly how they would go together. I simply want to fasten all of the parts together where they are without having to do a bunch of mates. I've tried simply grouping the parts in an assembly, the using that as…

I've got several parts in an assembly that will be welded together. So, in the assembly, I want them to move as one piece. The parts were created in the same studio so are already in the right location. The fasten mate works in some cases but I have a lot of problems when Onshape doesn't find any common mate points. I can…