Can I choose names for nnmaildir groups?

[Sean McAfee]

I use nnmaildir as my primary backend:

(setq gnus-secondary-select-methods
      '((nnmaildir "mail" (directory "/home/smcafee/.nnmaildir"))))

Within that directory, procmail divides my incoming mail into various
subdirectories.  In Gnus's group view, the groups representing those
subdirectories all have a common, longish prefix "nnmaildir+mail:".
That's a little cluttered, and I'd prefer to be able to name them
eg. "mail.list-1", "mail.list-2", etc.

Is this possible?  Extensive Googling and experimenting haven't turned
up any working solutions.