Some libraries want to say : "you can check-out 5 books at library A, 5 books at library B, and 7 books total"
That could be achieved by adding a "Global" or "Total" level to issuingrules. In this "Total" level, only the number of check-out is relevant (durations, ... are not)
isn't this one a duplicate of 8137?
I think the same behaviour could be achieved with this solution!