Can Grifana query multiple TSDB clusters?

We have a Hadoop cluster running on Ubuntu 14 which hosts OpenTSDB. We have now setup a new cluster on Ubuntu 16. I am having a hard time to copy the HBase data over. So, I am just thinking about a worst case scenario where we cutover all the clients to start writing to the new cluster. In this scenario data will reside in 2 clusters.

Does Grifana support like a sql union query where it can query multiple clusters and present the ‘unionized’ data?