Firstly, apologies if you've not seen this. It was launched a while ago, and I've only just stumbled upon it
https://youtu.be/HIJrktiaQ_o
Essentially, Limited Access Roles give you the ability to segment a Systems Manager network, so that admin A can only see devices that are tagged with a particular role. So, for example, the administrator of a hospital in Milan can only see devices in their dashboard that are tagged with Hospital-IT-Milan, for example.
Now, there's severa things you need to do
1. Create the role(s)
2. Create the admin(s)
3. Tag the devices
This ALSO works with SAML too:
Now, obviously, if you've a LOT of admins, roles, devices to tag / create, all of this can be done with the Meraki API
https://developer.cisco.com/meraki/api-v1/create-organization-sm-admins-role/
https://developer.cisco.com/meraki/api-v1/create-organization-admin/
https://developer.cisco.com/meraki/api-v1/modify-network-sm-devices-tags/
and, if using SAML
https://developer.cisco.com/meraki/api-v1/create-organization-saml-role/
Full details here: https://documentation.meraki.com/SM/Other_Topics/Limited_Access_Roles
and, for nostalgia:
https://meraki.cisco.com/blog/2015/06/limited-access-roles-for-systems-manager/