Use value for a slicer in a different way

I have a power bi report on a power bi report server, the report has a matrix which is filtered by 2 slicers to give data for a specific month, I would like to use the value in the slicer to filter the data in another matrix, but this one will return the totals for each of the previous 12 months

Does anyone know how, or if, I can do this using some DAX code or something like it

Any help much appreciated