I have done this many times on the CI side and recommended it to dealers since moving to the rep side. There is a little hacktastic to do on the XLR as you need to remove the heads on one side. You also want to make sure you sum at the euroblock connection as I am guessing you want summed to the sub and the sats and most of the DSPs built for the Crown amp will expect the signal to be summed prior to input.