Grouping data in the table view

I'm using this table to simulate tour data set:

I added a new column wich computes what I understoud from your explanation. The measure is this:

Column = 
VAR _CurMonth = T_Sales[Month]
VAR _Provider = T_Sales[Provider]
VAR _Result = 
    CALCULATE(
        AVERAGE(T_Sales[Sales]),
        FILTER(
            ALL(T_Sales),
            T_Sales[Month] = _CurMonth && T_Sales[Provider] = _Provider
        )
    )
            
RETURN
    _Result

And the final output is this:

For example, for provider A in January the Average is 150 ((100 + 200 / 2)), so this number repeats for each day of January for that provider. In February the Average will be diferent.
This is what you're looking for?