Would someone please be kind enough to show me how to setup and use the available nodes in Poser to accomplish this?

What I am wishing to do is use Simon's head texture map from Poser (head, mouth, tongue) but have my texture mapped head instead of Simon's, but letting the mouth and tongue still show from Poser.
I am wanting to do this through masking so users will be able to use Posers textures and my own (ie; illegal to distribute Poser textures, so I couldn't just copy and paste).

If I haven't made this clear let me know and I'll try to explain better what I'm wishing for.

Thanks to any or all that reply.

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