Event Reporting text

Hi
I would like to choose my own text for event reporting to SMS for enter/exit geofence zone for RUTX50 on a boat, for this BOATNAME is the name of the boat, and AREA1 is the name of the geofence
Currently I have set up the following
%ts
BOATNAME
%ex

this returns sms event of
2025-01-01 12:00:00
BOATNAME
Router left geofence AREA1 zone

I want it to send something like this
2025-01-01 12:00:00
BOATNAME left AREA1

I want to change the text sent in the sms from “Router left geofence AREA1 zone” not have the words router or zone in it, eg “boatname has left AREA1”

Is it possible to edit this wording in the background or create a script that will just display enter/exit of the geofence area name only?