How to combine Oracle RAC with in-memory database to isloate OLAP from OLTP

I am going through a document https://www.oracle.com/technetwork/database/options/database-in-memory-data-sheet-2338744.pdf There is a thing written "Oracle Real Application Clusters (RAC) can be combined with Oracle Database InMemory to isolate analytic workloads from OLTP workloads by running them on different servers of a cluster" Can anyone explain how would it be possible as RAC has the same storage under it and how can different nodes take responsibility of OLAP and OLTP workload independently