The first important thing is that there will be no fast roaming between Meraki and the other Cisco gear. For the concentrator implementation: The concentrator is typically placed in the DMZ. For each SSID you can choose to break out the traffic locally or to tunnel the traffic to one of your concentrators. This tunnelling is basically what you are doing with local mode and the local break out would be comparable to FlexConnect. An important point to consider is what you say about the different organisations: There are also organisations as a Meraki term where all devices and licenses of a company are combined. SSID tunnelling is only possible between devices in one organisation. If each of your organisations want to buy their own concentrators, then there is no tunnelling from your AP to their the other organisations concentrator. ... View more