By default when creating a record in CRM say a case you have to have the customer name which is a GUID fromthe SQL table of an on-premise CRM deployment.
I want to do the same but i want to search first.
So step by step
1. a user send a message to a group
2. MS flows get the phone number of the user
3. searchs the phone number on an onpremise database to get the GUID
4. with the GUID it created the record using the GUID on the customer name field