Have the Server drop-down list support name Aliases, so that in the drop down box, it'll display for example: Compaq Mail, and HP Mail... where those name aliases will map to ssl://mail.compaq.com:993 and ssl://mail.hp.com:993, but those server names wont be displayed to the end user, just the friendly aliases will.
By the way, this is implemented in Ilohamail, which I thought roundcube was built around, so it shouldn't be too hard to implement.