[Mark McLeod]

Technically of course there's no need to reimage cRIO's so that the robots use different team numbers.
It's a matter of keeping the networks separate and distinct.

It's all in the DLink settings and the Driver Stations connecting to them.
The DLinks each must have different different SSIDs so you can tell them apart (we usually name them for the robot), and you probably want Security on them enabled just to avoid any unintended automatic connections being made (especially between Driver Stations and DLinks). Use a browser to login to the DLink and look under the Wireless settings.
Don't allow any of the Driver Stations to automatically connect (unless they are exclusively used with that one particular robot).

Then manually connect each driver station to the DLink wireless of their choice through a Developer-type user account, then start the Driver Station app or login to a Driver-type account.

If it's a noisy wireless environment and you get too many packet collisions then you can force each DLink to avoid conflicts by using different sets of channels.