Audio feedback occurs

In the current state of technology, it's not possible to have multiple computers with audio active in the same space without manually muting the ones not being actually used.

The best way to get what your after is to use some kind of external speakerphone such as Jabra and connect that to one of the computers with the others having audio muted. Then, everyone around the table (?) is heard and hears from the one connection. They can still watch their own screens and be seen on their individual cameras.

If you have a larger group than can be accommodated with a single speakerphone, we have good luck with Yamaha YVC-1000 which can have up to 5 wired table mics.