Of course that's possible. I'd suggest Milkshape 3D over 3DS Max or any other high-poly modelling package for this, as it contains a HL model decompiler/compiler all in itself. It then takes some fiddling with the .qc file before you recompile it. I don't remember all the stuff exactly though, and it depends a bit on what exactly you want/need.
So, what model are we talking about, and what kind of problems are you having with these submodels?