N dynamic line charts in single graph panel

Hello, I am using ES 6.x datasource in latest grafana and I hit a problem.
My “documents” index looks like:


Currently I am having a time series line chart that shows number of documents with status:COMPLETED over time.
However the new requirement is to do N (e.g 10) lines on the same chart for the top N countries (the ones that have the highest number of COMPLETED documents within the $interval).

So, these N countries change over time, so they need to be dynamically resolved.
Could you please advise, what my options are?

Thanks in advance

Group by country with size N, before grouping my intervsl (date histigram) does exactly what I wanted. Elastic-templated dashboard was really helpful.