Need solution for Availability based assignment manager

The Requirement is Assign Issues (S_EVT_ACT) for staff members on daily basis. Whenever one of the staff is on vacation the assignment manager should skip assigning the issues to the particular staff in vacation. Does availability based assignment works only for Employee based or Could it be used for position based too? The Requirement is to assign the issues to the position candidates whose has the assignment skills.

Any comments on the approach is appreciated!