Yes you can, and no you don't have to. !!!

Yes you can have more than one email address in OE, open OE and click on Tools then Email Accounts. From here you can add more email address.

No you don't have to switch email accounts it will download each account individually and dump them all into the same Inbox with OE.

Hope this helps, if you need more info PM me and I will help as much as I can.

Good luck