Hello Dave, I think you can do this! I'm not familiar with the vSZ but I guess that in this way can be the same that a ZD.
I'll do it in this way, maybe is another easier that I don't know. Create 2 WLAN groups, selecting in one all the WLANs and in the other group all except the one that you don't want on the 5GHz band.
Then in the Access Point groups where belongs the APs, there is the "WLAN group" and you should select the group with all the WLANs for the 2.4GHz band and just next you can select the WLAN group for the 5GHz band where you should select the group that doesn't have the WLAN that you don't want on that band.
I hope that this can help you in the vSZ.