Sum two metrics from two different prometheus datasources in a single graph

Have prometheus server setup for each Geographic Region like North America, Europe, Asia, etc. Want to setup a global prometheus dashboard which shows summation of metrics from all regions.

I know about the mixed datasource mode on Grafana which allows you to graph multiple metrics from different datasources. But I would like to do aggregation functions on top of queries from different datasources like SumSeries(), max(), etc.

Example -
Query A (Datasource - North America) - rate(http_requests_total[5m])
Query B (Datasource - Europe) - rate(http_requests_total[5m])
Query C (Datasource -Mixed) - sumSeries(Query A, Query B) --> This what I am looking to graph i.e. Global QPS graph

Is there a way to achieve this?
PS : I am using a normal graph panel to visualise. Let me know in case you need anymore info if I didn’t convey it properly.


@varunwachaspati did you get any solution for this?