You can assign a selection (curves, follicles, CVs, hair system) to either an existing hair system or a new hair system.

If the selection consists of hairs that are currently part of another hair system and you assign this to a new hair system, the original hair system will be duplicated and the selected hairs attached to that duplicate. Thus this provides a means where one can take a few hairs and adjust hair system settings for just those hairs. Constraints on hairs are also transferred when assigning a hair system. If only a few of the hairs being constrained are reassigned, then the constraint will be duplicated such that each hair system has a constraint. If all the hairs being constrained are reassigned, then the constraint is completely moved to the new hair system and no new constraints are created.

To assign a selection to a hair system

1. Select the curves, follicles, CVs or hair system you want to assign. If your selection is follicles or CVs, convert the selection to curves.
2. Select Hair > Assign Hair System and then select either an existing hair system or a new hair system.