I have 3 accounts using one set of folders—Inbox, Sent etc—so yes, it's possible. I do remember it was a bit difficult to setup though.

I use POP for my email, so I can't say for sure if it's possible with IMAP.

If I recall correctly, the trick is to set the same PST file as the 'Data File' for each account. It's in:
File > Account Settings > Account Settings > click on an account > Data Files tab.
If IMAP uses a similar file setup, that should get you on the right track.

I also see a 'Change Folder' button on the Data Files screen, if you need it.