[Exim] Regexp Maps?

Okay, I have to admit that one of the features I like about Postfix is
the ability to use regexps for maps. Has anyone found a way to
implement something similar? And no, I'm not looking for a filter.

        --Jerry

name:  Jerry Alexandratos         ||  Open-Source software isn't a
phone: 703.599.6023               ||  matter of life or death...
email: jerry@???           ||  ...It's much more important
                                  ||  than that!