Different projects on one Mautic installation?

Hi there,
let me get directly to the point. I have multiple products/services i want to use mautic for. One is for councelling, another one is for a training plattform etc.
What i was thinking about was that if someone maybe unsubscribes my emails for the councelling the person will also be unsubscribed from the other projects.

So one idea is to have multiple Mautic installation - one for each project. But it would be much smoother to have all in one place. So i am thinking of a way that a unsubscribe link only opts out from a segment, but the person can still be contacted in the other segments.

Also - i have a segment for councelling prospects and one for clients. If a clients opts out from my prospects Newsletter i still would like to be able to contact this person als a client with productinformation on the product they already have bought.

So the unsubscribe-link ins problematic for me. has anyone had the same issue and solved it?

Thx.