We do it by assigning fairshare just to the account.
sacctmgr -i add account $acct Description="$descr" \
Organization="$org" fairshare=200 GrpJobsAccrue=8
sacctmgr -i add user "$u" DefaultAccount=$acct fairshare=parent
Add the same user to other accounts with
sacctmgr -i add
For this use case you probably want to go with Classic Fairshare
(https://slurm.schedmd.com/classic_fair_share.html) rather than
FairTree. Classic Fairshare behaves in a way similar to what you
describe. You can set up different bins for fairshare and then the user
can pull from them. So that
