Prevent Datasource connection from being overwritten on PBIX upload

Not sure if I'm missing something but we have 3 environemnts a Dev/UAT/Prod environment of PBIRS and each has their own SSAS instance to point to. We upload our PBIX files to each environment as and when we have changes to be published.

Every time we upload though we either have to change the connection in the PBIX before uploading or change it in the PBIRS datasource after uploading which is cumbersome. 

Is there a way to upload or publish without the connection string getting overwritten so that once it is set in each environment, it doesn't change.