I don't think the Scheduler has that capability.
This is something you'd need to do sort of manually, but it's probably not that hard to do. You'd insert your legal ID clip right into Playing Now at the appropriate time. You can figure out the right place to put it, by highlighting some files and then looking at the summary bar at the bottom, which will tell you the duration of the files you have selected. So, if it's 2:15 PM and you want to play the ID at 3:00 PM, select files until you get about 45 minutes worth. Then put the legal ID *right* after the group of files you selected. Then select 60 minutes more from there and insert another legal ID.
Like I said, a manual process, but not super hard. Just a little tedious.
Brian.