Hi,
you can enable either the 5GHz and/or the 2.4GHz on a per AP basis in the RF Profiles.
![rwiesmann_0-1608647346264.png rwiesmann_0-1608647346264.png](https://community.meraki.com/t5/image/serverpage/image-id/15934iD5A58E4B1CF5F62D/image-size/medium?v=v2&px=400)
See it in the documentation:
https://documentation.meraki.com/MR/Radio_Settings/RF_Profiles
I am not sure if this is also possible in the MX67W as I do not have such an MX. But i would expect it.
So on a per AP basis you can do it.
In your case you would need to go on a per SSID, where you can choose either dual band or 5GHZ only.
So I would try to implement one SSID with only 5GHZ.
The second I would try to configure dual band and just unassign all the channels of the 5GHz.
I am not sure if this will work...but I would try to do it this way.
hope it helps