Many years ago when my kids were first in school, our elementary was sharing a part-time art teacher with another school and the PTOs were paying for it. From what I remember, we just gave the money for her salary to the school and they handled her employment through their HR department. Could get a bit more tricky if your parent group has to operate as the employer.
Has anyone funded a teacher's salary through PTO funds? I'm researching this possibility for our schools, though I hope we are able to avoid such a drastic step!