Fairly easy:
What you need to do is have the coil on the side light feed, you could do this by just picking up on the dash illumination somewhere as that might be easier to get to.
Then if you put your feed (an ignition on feed) to the DRLs to Pin 30, and connect the DRLs to 87a, they will also be on, unless you turn the side lights on, which will energise the relay and break the circuit.