Google People API - Field which shows how it was last updated - in Google itself, or via API

I have created a system where my clients' Google Contacts are synched with Podio CRM. When a contact is updated in Google, the contact is updated in Podio (and the flow stops at that point). When a contact is updated in Podio, the contact is updated in Google (via the people API), which triggers an update in Podio (not wanted!) - I would like to filter this action based on what was the last 'thing' to update the Google record (ie. if it was the API then the flow stops)