Is there a way to use current selected filter values in formula fields?

This is the situation: the database is formed by records representing monthly income from different sellers.
There are many records for each month and for each seller, representing incomes from selling different kind of products.

In the filters users can select a range of months (es: from 1 to 3) and in a bar chart the corresponding sum of incomes for each seller for that range of months will be shown.

I'd like to add another view on which to show the perspective income for the whole year for each seller (calculated simply dividing the total income for the selected records for each seller by the number of months selected - in the example, 3 -and multiply it by 12)

In this way depending on the time interval filtered, different perspective incomes will be dinamically calculated.

So, I'd like to find a way to include into the formula the fact that I have selected only the records with months 1, 2 and 3.

Thanks and bye