Hi Tony - if I understand you correctly you want to get like 4 cylinder fragments to make glass panes?

Will these need to be solids, or is it ok to have a surface fragment there?

Basically instead of doing a boolean you're going to probably want to get a base surface in there and use Edit/Trim to cut it with those existing edge curves.

It will probably be easiest to do an "untrim" to recover the original surface of the outer piece without needing to create a new one, I will show you some steps in a minute here.

- Michael