how to subtract months giving a specific criteria

hi I have a rolling last 12 months in excel but I would like to exclude specific months so that way it will skip does months on the report. but the formula that I have wont work for every month. the months that I would like to skip is march 2020, april 2020, may 2020, june 2020. I have a drop list I which it will subtract the last 12 months. enter image description here