Auto Insert Advertising in Assist Mode

I use Mairlist v7.1.7 (Advanced Server) & we have payed ads at ± xx:15 and xx:45 of each hour.

The problem is, when in assist mode , I clear the queue because it is a program where listeners decide what to play (some kind of radio request show). We insert & select manually our songs in Assist mode
but the advertising need to be inserted automatically at ± xx:15 and xx:45 of each hour

Is there a way (or a script) , that ONLY the advertising (if any) will be inserted into the queue at the correct time?