Getting one section of model to move

I have a model of a magic portal. It is a circular portal, with a circular frame around it. They are all a part of the same .mdl model.

I am trying to make it so that the portal will slowly rotate, while the frame does not. The frame should stay in place while the portal inside moves in a rotating manner.

Is there a function or method to specify one piece of the model to perform a certain action like rotating, such as by a specific Group or something within the model? For instance, I notice the portal is Group #1 in the .mdl file, while pieces of the frame are other different Group numbers.

i think best solution would to part the model in 2 seperate models
easier to handle so 1 frame model 1 circle model.

I am not sure if one model can have 2 seperate animated parts at there own speed level.

Just animate only the portal in the some animation frames or add bone to the center of the portal, attach vertices to it, name the bone and use ent_bonerotate to rotate it around the angles you want.

Thank you Reconnoiter. I ended up just doing without the frame, but your post is making me think about putting it back in, for it sounds like it will work. I will try it, and let you know how it goes. Thank you.

Or attach a bone to that portal and use ent_bonerotate

np, to add to what alibaba said you can also combine them when you do ent_animate first and than ent_bonerotate. Depends on your exact needs. If you only want to rotate the portal than only ent_bonerotate is an easier solution.