It’s very easy, you just create a basic file that looks like this
<?xml version="1.0" encoding="utf-8"?>
<ModelMatchRuleSet>
</ModelMatchRuleSet>
Then you add
<ModelMatchRule CallsignPrefix="x" TypeCode="y" ModelName="z" />
x
is the callsign prefix; essentially anyone logged in with a callsign that begins with this alphanumeric sequence could be matched
y
is the ICAO type code that people have connected with, a list of all (current) type codes is available here
z
is the actual model, which you will find in the livery’s aircraft.cfg file as the title parameter
So, as an example, you have a Cirrus SR22 model for a specific callsign and want to match that to everyone who’s logged in as an SR22 with that callsign. The line could look like this
<ModelMatchRule CallsignPrefix="DECGB" TypeCode="SR22" ModelName="Cirrus SR22 D-ECGB" />
This won’t match to any SR22 unless it has this specific callsign, and vice versa it won’t match to anyone flying as DECGB unless they are using an SR22.
If I wanted to match this model to all SR22s that use a correct German registration for the type, I would not use the entire callsign, but only the DE part, so
<ModelMatchRule CallsignPrefix="DE" TypeCode="SR22" ModelName="Cirrus SR22 D-ECGB" />
And if I wanted to match that to all SR22s regardless of callsign, I could simply leave out the CallsignPrefix parameter like this
<ModelMatchRule TypeCode="SR22" ModelName="Cirrus SR22 D-ECGB" />
Now let’s say I had multiple SR22 models and wanted to match them randomly. In that case, I could simply specify multiple models for the ModelName parameter
<ModelMatchRule TypeCode="SR22" ModelName="Cirrus SR22 D-ECGB//SR 22 Livery 01//SR22 Asobo" />
So, of course, you could create a model matching file like the following (assuming what you used for your examples are the aircraft titles from the cfg files)
<?xml version="1.0" encoding="utf-8"?>
<ModelMatchRuleSet>
<ModelMatchRule CallsignPrefix="CHX" TypeCode="EC35" ModelName="adac xy h135 model" />
<ModelMatchRule CallsignPrefix="BPO" TypeCode="EC45" ModelName="police xy h145 model" />
</ModelMatchRuleSet>
and if you have more than one type for a specific callsign, say, an H145 using CHX, you can simply add another line to specify that, e.g.
<?xml version="1.0" encoding="utf-8"?>
<ModelMatchRuleSet>
<ModelMatchRule CallsignPrefix="CHX" TypeCode="EC35" ModelName="adac xy h135 model" />
<ModelMatchRule CallsignPrefix="CHX" TypeCode="EC45" ModelName="adac xy h135 model" />
<ModelMatchRule CallsignPrefix="BPO" TypeCode="EC45" ModelName="police xy h145 model" />
</ModelMatchRuleSet>