We have 6 query nodes but queries are using only 2

In our Couchbase cluster, we have 6 query nodes. But when we ingest heavy load of data we see that only 2 query nodes are getting used and they are maxing out on CPU and memory. Is there a way to distribute the load to all the query nodes. We are using the spark connector to insert data into couchbase.

I think I have found out the issue. this is not because that query nodes were not distributing the queries. It was happening based on round robin fashion. Each node was getting 17% of the queries. The problem with the two query nodes is that it is also an index node. The queries are using three indexes and those indexes are on those indexes only. That I think is spiking the memory and CPU. Ideally index nodes should have been on separate nodes.