You said that the devices exist in multiple Organizational Groups. Are you wanting to ignore specific groups, or look in only one group, or is the region name the same across all of the groups that the device can exist in?
You only need the 'Region' name. Are these names unique across the groups?
show region name where device guid is in a specific organizational group
or
show region name where device guid is in one of these regions (region1, region2, region3, etc)
or
show the first region name where device guid exists in any organization group.
or
?
Since you are looking to use a token, you are asking for only one value to be returned in the SQL and never more than one. What logic can be used to use to ensure that you only get one value back?
I see no reason why this can't be done, I just need more specifics before I can help.
Jason