SubFolders
There is not necessarily a folder structure other than grouping your list of programs by the portfolio they are in.
But for extra options, you could create a custom form that is attached to all programs, with a field(s) to apply whatever sort of organization you might want, the group by that field(s).
Agree, I was going to suggest a Program custom form too that tracks what you want across Programs and can have multiple program or project reports from there...
If this helped you, please mark correct to help others : )
