How To Manually Enter Resources on Resource Calendar?

My museum uses our resource calendar pretty regularly to keep track of all of our events (education tours, facility rentals, public programming, etc.), so that nothing gets overbooked. However, recently we had an issue where the space my department needed was only reserved for the duration of the event, and not the prep time before. Another department put a school tour in that space in the hour before our music event, which cut into our prep time for the event as our facilities team could not set-up the room while that school tour was going on. 

We don't want to change the time of the event itself to fix this problem. For example, our First Friday music event runs from 5:30-8pm, but we need to get the tables, chairs, and dancefloor set up before that. This means that event technically needs that resource space starting at 3pm. We would like to keep it as 2 separate things so that on the calendar it reads "3pm-5:30pm First Friday Prep" followed immediately by "5:30pm-8pm First Friday."

Is there a way in the resource calendar to manually put a booking in for that space without attaching it to an order (since an order would not be needed for internal use)?