How to keep my VA's anonymous?

Hi all,

[Do not message to be hired as a VA]

I operate a small business where I work with clients who seek me out for some services for their online business. The client understands that they are paired with one of my VAs, which is overlooked and guided by me, but the actual work done is 80% done by the VA.

This business model allows me to service multiple clients at once. Some clients prefer a WhatsApp group setup, typically including myself, my VA(s), and the client.

My problem is that this opens up the opportunity for the client to message the VA directly to conduct business outside of my company. Even if the VA does not act on this, it could be troublesome if the VA is no longer operating with our company.

My question is, how do others prevent this? How do they keep their VAs and clients anonymous but still able to communicate?