I know this doesn't help you with version 11.5.3, but if you upgrade to NPM version 12, you have the option to assign actions to alerts:
There is a similar option on the Action Manager tab that allows you to assign a particular action to an alert.
Loop1 Systems: SolarWinds Training and Professional Services
You are correct, that doesn't help. I upgraded from 10.7 to 11.5 just 3 weeks ago, and there is NO WAY we are upgrading again so soon or to a brandy new release.
This is a big miss on SolarWinds part!
BTW...Say Hello to Steve K for me.