I have (I believe) a DP-34 switch and both of my 721's hooked up off of that. I purchased a second DP-34 switch. Can I hook the second up then then hook the 322 off of the second switch?
You can, but it would be more reliable to have the 322 feeds running from the same switch. Had some problems doing it like that in the past with seperate feeds on different switches.
just run the connectors on the right side of the first switch to the ones on the left side of the second one. At least one receiver on the first switch must be powered at all times for the second to function.