So, our Meraki setup was done by a company long bought out by another massive company so we have no dealings with them anymore. This was years ago, before 2018 when I started.
Back then it appears SSIDs were created for sites, but then those sites had TAGS applied that would broadcast only specific SSIDs at specific sites.
I've looked through the two pages of documentation that talk about TAGS but neither of them explain how you edit or create those tags.
https://documentation.meraki.com/MR/Other_Topics/Using_Tags_to_Broadcast_SSIDs_from_Specific_APs
https://documentation.meraki.com/MR/Monitoring_and_Reporting/Using_Tags_to_Manage_MR_Access_Points
I'm currently having an issue where we've replaced Meraki APs at some sites, for newer APs that are in support. Turned on the SSID for one site as an example and all the SSIDs that used to be broadcast on that site are no longer broadcasting. You hoover over the tag and it explains its not being broadcast and needs one of the TAGS for that SSID to be broadcast on that AP. But I can't find those TAGS anywhere to edit. Also, if I highlight the AP and add tag, the tag requires isn't in the list. But if you go to WIRELESS/SSID availability the tag is there and applied to the AP, yet it still refuses to broadcast the SSID required. And again, I can't find where those TAGS were ever setup.