Filter log messages by program name and log level at the same time in rsyslogd
This example on the rsyslogd wiki suggests a way to do something like you want. It's the Filtering by program name using the expression-based syntax part.
Using the example provided on the wiki:
if $programname == 'foobar' and $syslogseverity-text == 'error' then /var/log/foobar.log
Put that on rsyslogd.conf or as a snippet inside rsyslog.d
a simple way to do that is ... if ( $program contains "foobar" ) and ( $severity contains "err" ) then /var/log/foobar.log
Of course there are many other ways, but i think that the above is quite straight forward.