primary care office looking to bring on a NP of dermatology

So our office is looking at adding an NP of dermatology to the office. As you know we are primary care. I was wondering if anyone had some answers to the questions we have re billing and credentialing her.

• can we bring in a specialty NP under our tax ID and them be paid FFS or would they be capped as well?
• can we refer to her the same day she is in the office with another provider and get paid being it's a different specialty?
• do we have to change the group designation from...

primary care office looking to bring on a NP of dermatology