I think it's simpler than you think. If you're interested, check out this nifty interactive page on networking (the "Daisy Chain" part), which looks like this:
However, your situation sounds simpler since instead of all the stuff connected by blue lines in that "Animated Demo," you could just have the one PC connected directly to one EB which is connected to the next EB, like this:
One thing that gives me pause is your use of the terms "primary" and "secondary." I'm hoping you just mean the 1st in the chain and the 2nd (rather than a redundancy thing).
If you are trying to do something with redundancy, then I'd wonder about the odd (as in, not a multiple of 2) number of modules. You're not talking about redundancy here, are you?