It it possible to create user-defined syslog facilities?

For example, I put the following in /etc/rsyslog.conf

local7.* -/var/log/myapp/myapp;RSYSLOG_TraditionalFileFormat

I then enter the following on the command-line:

$ logger -p "test of logging to local7"
resulting in the following line being written to /var/log/myapp/myapp

Apr 2 14:42:36 ngssuse ngsshatt: test of logging to local7

What I want is a way - other than using an environment variable - to replace with as the -p argument in the logger command and achieve the same result.

Is that possible?