So far from what I can tell for setting library hours and closures there is only one set range for setting hours and if you set a closure it is for a whole day. I asked support about this and it was confirmed that this is the case.
A great feature would be if Library Admin could either set two ranges of hours for each day OR to set a repeating closure for a specific range of hour(s) on any given day of the week (and not for the whole day, which is the only current closure option).
For example our Friday hours are typically 7:30am-3pm and 4pm-6pm as we close for an academic lectureship each week that happens from 3-4pm. I know there are other colleges that have chapels that could benefit from this flexibility too.