I wrote an email to him. If someone finds this topic searching for answer, I gave him 2 ways of doing this.
For each Closed Trade (set "Not more than n trades" to 1) -> check age -> do something. The first block loads the last closed trade only, then "check age" will check how old is it, and then if its old enough continue with whatever blocks are connected next.
In "on Trade" place Trade closed -> Skip Ticks. This "Skip Ticks" block would prevent "on Tick" from working for certain amount of minutes, which means that anything in "on Tick" will stop working for this time.