Yes, it would depend on the group, but it's pretty rare. More than likely you would have to create a position for yourself and sell them on the idea. Otherwise, just work two part time jobs, or one full time and the other part time. I know many PAs who do this to get money from one and personal satisfaction from the other.
P.S. I highly recommend what you are thinking about. It's always good to have more than one cert or specialty experience. Both will make you a better clinician (you'll be the best intubating practitioner in the department for sure) and if things go south in one then you have the other.