[exim] regular expressions in aliases

hi!

only the following local parts of a domain are valid:

^klaus[.-](m|maria)\.pfei[f]+er$
^kmp[+-.][a-zA-Z0-9.]*$
^kmp$
^klaus[+-.][a-zA-Z0-9]*$
^klaus$

my solution now is the following:
I have a catch-all in the system aliases and do filtering in the users
exim filter.

the problem is, that I would like to have a reject at SMTP time with
code 550, but in the users exim filter I can only generate a bounce.

any ideas how to achieve this?

I searched for regular expressions in the system aliases file, but
haven't found any solution. (only found that postfix is able to handle
regexp in alias files.)

I'm using exim 4.60 on debian testing with split configuration.

greetings & many thanks, Klaus