The job group does not have to exist before submitting the job.
bsub -g /risk_group/portfolio1/current myjob
Job <105> is submitted to default queue.
Submits myjob to the job group /risk_group/portfolio1/current.
If group /risk_group/portfolio1/current exists, job 105 is attached to the job group.
If group /risk_group/portfolio1/current does not exist, LSF checks its parent recursively, and if no groups in the hierarchy exist, all three job groups are created with the specified hierarchy and the job is attached to group.