A better way would be to avoid splitters altogether. Instead, get a Jensen subwoofer signal transformer http://www.jensen-transformers.com with a single XLR in, and any number and mix of XLR's and SE's out (they'll make up anything you need) They are excellent audiophile quality. Call and ask for Dave and explain what you want to do. It will eliminate the ground loop problems and probably save you some cable cost.
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