Unfortunately, the position and size attributes cannot be set dynamically. See this recent thread: http://forum-en.filemaker.com/t5/Using-FileMaker-Pro/Dynamic-positioning/m-p/66806. This is kind of a bummer, I know. I don't exactly see why this isn't implemented.
If you want to display the schedule in pure text as depicted, you could define a field for each classroom with calculated contents according to the times of each class, i.e. insert the class strings and as many "-" (or perhaps spaces) as needed.
EDIT: typos fixed
Thanks for the reply, even if it was the answer I feared I was going to end up with. It seems like it would be an easy tweak to the filemaker software - maybe something for a later version.
I will think about how to incorporate your idea into my database. The classroom schedules are not a necessary feature, but it would be so convenient if I could generate them automatically.