Modular 3D modeling for a game's 'Character Design' feature

First, thanks for any help you can give me - I am really stuck!

I am trying to create something the character-creators one sees with most RPGs and some simulation games. Its the screen where you choose hair style, hair color, ear shape, clothing, etc. In The Sims its where you create your sim. I am trying to figure out how to build 3D models so the parts are interchangeable...

I am good with 3D character modeling, rigging, etc... and I know how to build this feature for 2D games. However, I don't know how I should go about modeling and scripting interchangeable components for this type of game feature in 3D. Do you know of any good tutorials that could help me? Or perhaps a general strategy? I mainly work in 3D Max and Maya.

I was thinking I should make each component (e.g. hair, eyes, ears) separately and group them for animation? Should I make some things separate groups (e.g. hair) and others modify with some sort of distorter (e.g. eyes, jaw)?

I really appreciate any help you can give! Thank you.