Have you considered something like this?

There are two, three, or more companies that use Upbase (they have their own Upbase within their companies).

However, it's a completely different own Workspace for each company.

The idea is for these different companies to be able to work in their own Workspace while collaborating with other clients who also use Upbase.

Switching between Workspaces won't work.

This needs to be solved differently.