How to find common & uncommon items monthwise

Hi,

Need help with DAX, i have a table created using a folder of files, where i will be adding a file every month to the folder, i have a columns with parts(list of parts including duplicates), priority, month etc i want to find the part count that are common in both the months(previous & current), the parts removed from previous month & new parts added to current month, based on their priority. I want the DAX to work every month automatically as in when i add new file every month. I also want to find the standard deviation in part count with respect to priority.  TIA

something like this,

P.S:Priority is dynamic