Hi, @Mutcha
That's a complicated issue.
I think it is quicker to actually try it.
I experimented with the following results.
I sign in to account "a" on PC(A) and start a Meeting.
Then I sign in to account "a" on PC(B).
The account on PC(A) is forcibly signed out, but I am not forcibly ejected from the meeting I am participating in.
My organization's account allows one account to host up to two meetings at the same time, so both PC(A) and PC(B) were able to host the meeting, but in general, one account can host only one meeting at a time, so one of them must be a participant in the meeting.