This use case extend [Use Case 1]: you don't want some commands or some scripts submitted by a user can run at the same time, but you want parallel execution for some different commands/scripts. The typical usage is related to crontab and the chance some command runs late due to an undesired condition.
tiian@mojan:/usr$ flom -r R1 -- sleep 10 tiian@mojan:/usr$
tiian@mojan:/usr$ flom -r R1 -- ls bin games include lib lib64 local sbin share src tiian@mojan:/usr$
tiian@mojan:~$ flom -r R2 -- sleep 5 tiian@mojan:~$
tiian@mojan:~$ flom -r R2 -- echo Hello World Hello World tiian@mojan:~$
The commands executed inside terminals 1 and 2 synchronize on resource "R1"; the commands executed inside terminals 3 and 4 synchronize on resource "R2".
"Hello World" is displayed before directory content ("ls" command) because the two synchronize on different resources.
Independent commands can be grouped and synchronized using distinct resources.
Argument "-r" (long form is "--resource-name") can be used to specify the resource you want to synchronize on; you may use "Resource/Name" property inside configuration files as an alternative way to specify a non default resource.
Flom available arguments are documented in man page: use man flom.
Flom [Configuration] explains how you can specify flom behavior without using command line arguments.