Filter based on 2 columns and show missing months

When doing a chart with time period on X axis and number of validation on Y axis, I would like to be able to filter based on 2 columns (valid_from and valid_to dates) in the same range filter. Also I would need to display the months included within my validity period and for which there is no data. 

Ex.: for a promo valid from 01 jan. 2017 until 8 may 2017 with 0 validations in January, 50 in February, 0 in March, 350 in April, and 0 in May, Spotfire will display the month of February, March and April, but not the months of January and May, even if they are within the validity period. Or in my case, this is pretty interesting to know that at the beginning and the end of my promo it did not work at all.