Percentiles by group and date

Good morning community, 

I have tried all my tricks and I cannot figure out how to recreate the graph below in Power Bi. Please help!

For reference, my data includes individual-level data, each individual belongs to a department within the organization. The line in dark blue represents the mean of a specific measure for the entire organization. The line in light blue is the mean of the same measure for one specific department within the organization. The light green area is the score between the 25th and 50th percentile for all the departments in the organization and the light red area is the score between 50th and 75th percentile for all the department in the organization. To add complexity all the measures are calculated by date (month, quarter, year - in the graph you see the data by quarter). 

My question to you all is: 

how do I calculate departments percentiles by date? and how do I color in between lines?

Any direction would be extremely helpful, 

Warmest regards, 

Estefania