Linking CDJ2000 to CDJ2000NXS2 via external ethernet switch

I currently own 2 x CDJ2000NXS2 and am looking to add another pair of CDJ's to increase my total to 4. I am thinking that the original CDJ2000 would be suitable as a back up pair but I would also like to be able to use all 4 at the same time and have them all linked together via an external router.

I am hoping that someone can confirm that this is possible as I have seen some notes somewhere saying that the original CDJ2000 will not link with later models via the Pro DJ Link and an external ethernet switch.