Question About Modular Weapons

I bought a weapon from FAB which has modular parts. It consists of a bunch of skeletal meshes. Some have animations that work with them. My weapon system uses a structure that provides a single skeletal mesh to a socket and attaches it to the player. The only way I know to put all of the weapon parts together is inside of a blueprint (which is the way the demo did it). The problem I have is how do I combine these parts into a single skeletal mesh that I can use in the structure. Any thoughts?