Support for Query Based Credentials to run condition based Data Sources in the Power BI Service.

I discovered that a condition on the data source in my M query will not run in the Power BI service.
I.e. It the report containing it cannot be scheduled with a message that these are not unsupported. I have to thus set up each data source separately, allow them to run and only chose the results when I have loaded them. This is very inefficient.
Surely If we could set credentials at the level of a group of queries or functions rather than just for each data source the data sources called by that group could automatically run with those credentials. I could then use the "Power" of the M query to only load the relevant data required and save a lot of unnecessary processing. - Good for the environment.