Manually adding multiple users to a user account

I need to make it possible for my users to have multiple log ins per accounts.

For instance: if an institution buys a 4 seats membership, then each of the users should be able to log in, using their own login.

And then:
I need to manually add the extra users to already existing accounts, what is the best way to do all thhis?

I realize I can just create more WP accounts, but I need the extra logins to be associated to the main user account – so that if I delete a main account – the associated logins will be deleted also.

Is all this possible with Paid memberships Pro?

Thanks
John

https://ww.wp.xz.cn/plugins/paid-memberships-pro/