it's very odd that they would configure with dedicated storage group but it is what it is at this point. So the new box once zones should auto-register itself. Create a new group and add all the LUNs that you  have already presented to other ESX hosts. It's very important that you specify identical Host ID for each LUN just like it is in other storage groups, add the host to storage group as well. After that is done, you can rescan ESXi for datastores and they should pop right in.
At the moment we are running an EMC Clariion CX3-10 through two Brocade FC switches, back to a pair of Dell R900 servers running ESXi 4.1. This works well, however we now need to add an additional server to the ESXi cluster. I have got a Dell R710 and enabled EVC so the VMware side of things is fine, the question I have is what is the recommended procedure for adding this server to the SAN?  When the guy from Dell set it up initially, he configured a storage group per server - when LUNs are created these are added to both storage groups, thereby making them visible on both. I presume I need to create another storage group for my new server and add the same LUNs to it, is this correct? I presume the LUNs will present at the new ESX host with the same LUN IDs as they do for the other two hosts? I am also assuming that the unit will auto-register with the SAN, and all I then need to do is to add the host to the newly created storage group, prior to adding the existing LUNs?  Sorry if this sounds a little vague, but I'm more of a VMware man than EMC....  Cheers  JD
How to add additional server to EMC Clariion CX3-10 based cluster - help?