- Merging Meshes into One Mesh and dividing them in Mesh Groups -

I apologise if the OP is not too clear, I’m still a newbie:

If I have 1 imported obj imported, split into more Meshes (Body, Shoes, Accessories, etc) is there a way to merge it into 1 Mesh (like Ctrl + J) but at the same time making sure that all the Meshes will belong to separate groups in the same Mesh, so that I can easily reselect them later and keep the premade UV mapping?

I may be mistaken, but I can’t seem to make the armature work too well with more than 1 mesh.