Customising message subject in email alerts

xymon alert emails include the URL:

"See http://xymon.example.com/xymon-cgi/svcstatus.sh?HOST=webapps-cf4.bo3.e-dialog.com&SERVICE=procs";

I don't remember if it's in BBALPHAMSG, but you can stitch it together
yourself from your host name and the service name, which you have as
BBHOSTNAME and BBSVCNAME

Now if you want the parent page that's trickier.