On restart and reconfiguration, mbatchd invokes the egroup executable to retrieve external host and user groups and then creates the groups in memory; mbatchd does not write the groups to lsb.hosts or lsb.users. The egroup executable runs under the same user account as mbatchd. By default, this is the primary cluster administrator account.
Once LSF creates the groups in memory, the external host and user groups work the same way as any other LSF host and user groups, including configuration and batch command usage.