freeswitch failover on certain termination causes

Hi I have a quite straightforward freeswitch configuration
and I'm currently using freeswitch's failover feature
with the directive:

<action application="transfer" data="cfailover1"/>
...

it works decently but I'd like to be able to failover (to the next trunk) only on a given list of 'dispositions' and/or 'hangup causes'

to be more clean, i'd like to discriminate based on the following variables:
${originate_disposition}
${endpoint_disposition}
${hangup_cause}
${last_bridge_hangup_cause}
${bridge_hangup_cause}

please contact me if you are a freeswitch billing expert
and consider that I'm open mind about your suggestions
since I'm probably missing something with all those termination causes :)