You had me curious because I couldn't remember what I bought for my daughter when we were shooting USPSA.
We both have dedicated belts that use velcro - you can adjust them so they hang at the perfect height for rapid draw once the buzzer sounds.
So neither of our holsters (or mag holders) hang off our regular clothing belts.
With that said, I use the one that came with my XD, and for her G17, we have one that has quite a bit of adjustment from Blackhawk. I must have picked that up locally as I've got no record of any online purchase for it. It's not what you'd need, but posting a pic so you can look it up and possibly find something suitable from them?