You could get fancy with the rules, and use rules that mark the traffic based on criteria, and then use those markings in your rules to allow or block, etc.
You can do that with floating rules, that are not set as quick..
So you could mark or tag traffic based on criteria XYZ, and then in later rule on floating do something else with it like send it out a specific gateway. Or on your interface rules look for specific tag and then do X with it..
So he could in his floating rules, non quick set a tag for traffic to tun1, or tun2 or wan.. Then in the interface or floating (later down the rule set) set a rule that is quick that sends it out a specific gateway, or on the interface have rules that say if tagged tun1 send out tun1, if 2 out tun2 if wan out wan, etc. etc..