You can't commit a single Hotfix if you have already deployed more than one. All the uncommitted Hotfixes are grouped together, so if you perform commit it will commit all the Hotfixes.
Ideally, a developer should deploy only one DL items and verify the reported issue it intends to address and perform other regression testings to make sure the deployed Hfix doesn't breaks up any functionality. And then commit this Hotfix, or rollback it. It helps in isolation of issue if any after deployment.
Though, if a DL items have multiple Hotfixes they are all considered as the group.
Ideally this should be the scenario which you rightly said, but we work as administrators and apply multiple hotfix for multiple issues, and we have a situation here in which we need to rollback one couple of uncommitted hotfix and commit an another hotfix which is solely for a different issue,
Yes we can roll back all of them and then can install and commit the required one, but we should have an option here like a checkbox to mark and commit is what i was looking for, then again its just my thought, still looking for answers though.