Currently when you suspend a hold in Koha, you have the choice of adding a suspend until date. If the date is left blank the hold is suspended indefinitely, even if DefaultHoldExpiration system preferences are configured. 

When the hold is unsuspended after the hold expiration date, it is canceled. 

Being able to limit the amount of time a hold can be suspended would make the holds timeline clearer to patrons. It would also make determining how many copies are needed to fill holds. 

This could take the form of a system preference that adds the date limitation into the staff interface.