It is possible, you need to use the regular ES package rather than the OSS.
You need to setup I.L.M (free since ES 6.8) :
Setup an ILM policy
Add another index template with the same index_pattern of the “graylog-internal” template, to map this template to the indices. In this template, link it to your ILM policy, set the routing.allocation to your «hot» nodes, set “order” to a positive integer.