Models with Multiple Textures for one obj HELP

So a friend of mine gave me all of his models for twinsanity (not giving them away yet he doesnt want them to get out till there rigged for gmod) and they have multiple textures for a single object (when loading the .obj file theres only one mesh) and there is textures for the leaves which need to be transparent and they have multiple textures can someone help me? he told me about it having material ids but since there is no mtl file and also 3ds max is a bitch (he saved them in 3ds max) and wont load the material ids I am screwed so pls help me