Use 'identifier' property in GET and POST requests for Phone Location

Is your feature request related to a problem? Please describe.
When attempting to automate the maintenance of emergency service locations, it would be helpful to have a custom ‘identifier’ property that can be used in place of the generated id. An automated process will not have access to the generated IDs, and requires paging through the entire dataset of phone locations to determine if an incoming request is a new location or an update to an existing record.

Describe the solution you’d like
The needed field already exists in the phone location data (identifier). However it can only be set via a batch update and is only returned in the GET response for a single record. I would like the ability to set the ‘identifier’ field in the POST request for a single location. More importantly, I would like the ability to GET a single record using the ‘identifier’ field rather than the ‘id’