The updateCoreGroupCoordinators parameter allows you to adjust number of coordinators for the core group as well as the preferred coordinator servers list. This modifies the coregroup.xml file in <ND_install_root>/config/cells/<cell_name>/coregroups/DefaultCoreGroup directory.
-numCoordinators <number> Number of active coordinators for the core group.
-preferredCoordinatorServers <server list> List of servers that will be
coordinators for the core group, of the form <node>/<server>,
<node>/<server>, <node>/<server>, ...
[root@wpfsample3 bin]# ./wpfadmin updateCoreGroupCoordinators -numCoordinators 4 -preferredCoordinatorServers wpfsample2/s7,wpfsample3/s1, wpfsample3/s9,wpfsample2/s5 WASX7209I: Connected to process "Deployment Manager" on node wpfsample3Manager using SOAP connector; The type of process is: DeploymentManager The coordinators for the core group has been updated