Box plots for different time periods using same axis

I have a table which looks something like this:

I will attach the complet excel sheet for reference.

Description: The table has an Entity column where we have the "product" mentioned. We have Months column and Year column. The "Value" column indicates the value for the entity every month in every year. 

I would like the user to compare values of the Entity for given periods, hence in the column "MeasureType",  then entire rows for the "Entity" are duplicated with the same values just the "MeasureType" changes to Relative_value. This helps us to compare time periods by duplicating the data.

I would like to create box plots for calculating the distribution of values over months for the years selected by the user. Eventual visual should have 2 box plots:

1) for the relative_value period selected 2) for the new_value period 

How can I do this on the same axis giving the user two filters - to select the different time periods?

Eg: 

Filter1: "New_year" - 2020, 2021

Filter2: "Relative_Year" - 2018, 2019

The values should be selected using the "New_value" for the years 2020, 2021 and the values should be selected for "Relative_value" for the years 2018 and 2019. How do I display the distribution of these values in box plots?

reference_sheet - Here is an example sheet for the data