[exim] access of filter-files with psql

Hi all,
is it possible to specify the exim or sieve filter file
in the userforward_router not only with
file = $home/.forward
but as a psql query?
What syntax do I need?

Many thanks
Rainer Sigl
-- 
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Rainer Sigl,                      | email: sigl@???
MPI f. extraterrestrische Physik, | phone: +49 (89) 30000-3557
Postfach 1312,                    | fax:   +49 (89) 30000-3569
D-85741 Garching, Germany         | web:   http://www.mpe.mpg.de/~sigl/