Multiple Hubspot Instances

Hi - I have multiple companies I manage, each are connected to Zoom. Currently those companies are all connected via Hubspot to the same Zoom account, where we run our webinars across all of our companies for. I noticed recently that Zoom is syncing and creating contacts whenever a contact signs up for a registration across all of my connected Hubspot Instances. I'd like this to not be the case.

What is the best way to set up and connect a single zoom account to multiple external tools (Hubspot instances) to prevent this?