how to clone a pop definition?

I have multiple gmail and multiple yahoo addresses (as well as a few at more obscure sites). These only differ in the user name and password. Is there some way to clone (i.e., make a copy of) a pop definition and then just change these few things so that I don't have to set the port and the pop.smtp.mail etc. each time? I thought I saw something that suggested this in a help note but I can't figure out how to clone an existing definition.  It's easy enough to clone an "identity," but I'm interested in cloning a "definition."