Deleting session host - Messaging delay - allow indefinite until last user is logged off

As the title suggests when deleting a session host manually from a host pool there is the messaging section that allows you to send a message to the users on that specific host along with a timed waiting period which currently only goes up to 60 minutes, we would like to see an option of waiting till the user logs off, which could be numerous hours but once they have logged off the process continues as normal