if you go to edit dialog of advanced alert and click on "Trigger Condition" tab, there is "Do not trigger this action until condition exists for more than ...". There you can set minimal time to little more than transaction polling frequency to get desired result. so if you poll transactions every 5 minutes, setting this to let's say 10 minutes can work just fine.
Just keep in mind that if you have lot of transactions on a specific player, they may not be played every 5 minutes but it can take longer. In that case you may need to increase this number.