is there a way to modify a whole dashboard or at list one graph in data visualizer to display 3 indicators on the X-axis, with 2 bars per indicator (data collected monthly) — one for each year’s 9-month aggregated total without creating a new indicator containing the aggregated data.
Hey! 
Welcome to the DHIS2 Community of Practice! 
Regarding your question, would you like to provide a use-case as an example? Thanks!