Accessing Yahoo Mail

Hello. I use Mac Mail to access my Yahoo mail. When I send an email, it goes in the "Sent" folder beneath the "Inbox" folder. However, if I view my emails in Yahoo, they don't always appear in the sent folder on yahoo. AND there are two sent folders in Mail -- one as I described, and another along with my other archive folders called "Sent Messages" -- How can I get all of my sent emails synced in the same folder regardless of Yahoo or Mail access? Thanks!!!!