How to employ H1B on temporary basis

Hi,
This is codesmith, I've completed my green card journey with this blog :).
Few of my H1 friends who work for a client who filed their H1 and green card, want to work part time for another client/s and provide technical consultancy.
They can not start the assignment since the prospective client needs "some company" to deal with and for payments.
These guys gave me a proposal of starting a company and show them as employee and pay them major share of the payments received.

Is it possible to employ a person who is already having an H1 ? If so what's the procedure ?

Also, please suggest me any law-firm who can help me with legal aspects/paper work- just in case.

Thanks