It's possible if he does everything right. But the presumption by determining authorities seems to be in the 'employee' direction, so it's very easy to slip up.

Does he tell them when to work? Employee. How to do their work (a checklist)? Employee. Provide supplies? Employee. Do they wear a 'Maid In Black' uniform? Employee.

If he were a matching service, it might be easier. But, he's extending his brand/guarantee/monitoring over the service, so he may have to thread-a-needle to win any challenge that a regulator or (perhaps more likely) disgruntled contractor raises.