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Using Serato, you can't use two computers with a single pair of CDJs as you would with the mixer -- which has dual USB support. The only way to do what you're looking for would be to connect one CDJ to each computer and mix in "amputate" mode.
In "amputate" mode you effectively only have one deck being controlled, the other is an internal deck, so you load your tracks on the deck with the controller, then instant-double it to the internal deck (making sure to transition on the mixer accordingly as well), then unload the deck for which you have hardware control and repeat the process.