Yes, you can with Unwrap UV just select the faces and UV map them seperately, unfortunately in my version of max, at times this method proves... hehe, unreliable and ulitmately slower.
It depends on personal preferences I guess, and you are probably much more experienced at UV mapping than me.
I'm not sure a pelt map would work on the interior, you might be able to apply the pelt map then edit the UV map created, though are you sure you shouldn't just make the UV from scratch? And is it all going to use the same texture? (If not mesh ripping needs to be done anyway).
And before UV mapping it, I'm wondering if there should be edits made to the model first, I mean shouldn't you create a tileset of some sort, maybe link it to an underground cave tilest or have Pods like the telvanni, except they grow under the roots.
Otherwise all the interiors in this style become boring clones of each other.
edit: You could make a blank pod (which would be easy enough to model, and would also make it easier to UV map), then have seperate static walls which you can place in it, allowing the pods to be unique to some extent.
All good ideas I think. It's all up to Zackg & rhymer.
I'm guessing that one texture for the entire pod is a bit of a stretch so there will be multi-texturing involved, probably. It's been a while since I used the pelt map. My line of thought was to devide the mesh with the pelt map seams and then use some tools.
Of course I would edit it as well to get a good end result.
You seem pretty knowledgable tho. My knowledge is at best making uvmap for heads/more complex organics, or rather the most advanced I have ever delved into. Altho, one could argue meshes with insides might be a level above that. hehe.