How to hex more than one weapon model that uses the same textures?

I recently downloaded an xm8 model and I wanted to hex 2 versions of it; silenced and unsilenced. The only problem is that they both end up either being the same exact model (either both have a silencer or neither has one) or the textures are pink and black on both. I’ve seen a few packs that have models with different attachments on them and use the same textures, but I dont know how to do so myself. Anyone know how to?

Note: as reference, the packs I was talking about that “share” textures are:
-Slict43’s/ATOM"s MW2 Sweps
-GDCW Sweps
The MW2 weapons have multiple versions of the AUG that use the same texture, and the GDCW weapons (ex: ak47) use the exact same textures.

http://www.facepunch.com/showthread.php?t=880556

I made a tutorial for hexing if that what you mean.

If they use the same textures just hex the name of the models.