I'm not an expert, but from what I've seen, it is. You can forward your emails to your email that is set up on RoundCube. In RoundCube, you can create identities in your PERSONAL PREFERENCES.
From what I've tested, I can switch which Identity I want to send from and it goes over with that Identity. You just HAVE to remember to go over and pick the identity you want to send from when you create a new email.
And likewise, emails sent to my yahoo email and other email addresses, come over with that identities so you know which account it's from. Hope that made sense.