Margin relief for futures spreads?

Futuresnoob 

Has anyone heard of a broker that offers reduced margin requirements when doing futures pairs or spreads? I wanted to go long /RBH7 (RBOB Gas) and Short /CLH7 without having to pay full margin on both sides. I ended up putting the trade on using ETF's but really missed out on the leverage of futures. Thanks you any help.

1. Advantage Futures, or

2. Infinity Futures.