My prefered solution would be an additional limit of one unbound spirit sent on remote at a time.
So you could have one unbound spirit on remote, one unbound spirit nearby, and up to Cha bound spirits (doing whatever, remote or otherwise).
All that has nothing to do with my house rule for remote services, though, which is completely seperate from the multiple remote services issue, as explained somewhere above already (posts are easy to miss in this mess for sure, though
). I would use that in addition, simply because it makes no sense to me, that it is a remote service, if it doesn't happen in a remote location (at least remote at the time you gave the order, that is).
Bye
Thanee