Thanks for the suggestions! Bruce, my problem was stemming from having email for 69 different people within a hospital getting routed to the wrong mailserver. So all that email, over 300 emails, is all sitting in the Horde Inbox...jumbled together. When we switched the site over, they wanted to keep using a local company for their email, and I didn't know enough about it to get the mailserver info. correct in the beginning. So, it's all my fault, really! Live and learn! At least they understood and weren't upset with me!!
Plus, for whatever reason that is beyond me...the hospital can't seem to access their .com domain. Everyone else in the world can, but not them!
Anyway...I think we will actually be able to do it without doing what I had asked about. We got the mailserver issue fixed, so now 2 of us should be able to log in to Horde and just forward the emails to their correct accounts. It'll take a while...but at least it should work.