LUN Sharing between two Cluster

We have two clusters having LUNs from VMAX Storage Array with same Port Group.

Cluster A having 3 ESXi hosts

Cluster B having 15 ESXi hosts

Cluster A having 3 LUN which has to be shared with Cluster B having 15 ESXi hosts

Cluster B having 15 ESXi hosts having 40 LUNs which has to be shared with Cluster A

i need to share the LUNS without downtime