When initiating an Overtime CallBack, you will be given the choice of what 'List' to hire from. Think of the 'Lists' as being three ring binders, with each binder full of employee names. You could have a binder called 'Special Events' or even a simple binder called 'Firefighter'. When hiring back personnel via CallBack, you select the list (aka Binder) to pull from. This means that the system will only contact eligible employees, who are within that list (aka binder).
Scenario 1) Lets say John Smith is in the Special Events list but not in the Firefighter list . An overtime opportunity comes up, and a shift manager initiates a CallBack, utilizing the Special Events list. John Smith would be eligible for that overtime shift, and depending on where he currently sat in the list, he would be offered the overtime. Depending on your Organization's overtime list rules; he would either then be moved to the back of the firefighter list, moved in all lists he is a member of, only moved if he accepted, moved regardless if he accepted or denied, or any number of other variables all dependent on your organizations rules.
Scenario 2) Lets say in the same scenario above, the manager chose the Firefighter list instead to hire from. John Smith would never be contacted for the shift, as he was not in the Firefighter list. Only employees who were a part of the Firefighter list would be contacted.
Scenario 3) John Smith is a member of both the Firefighter list and also the Special Events list. If a CallBack was initiated for either of these lists; he would be contacted.
It is important to note that an employee can be a member of unlimited number of lists.
You can see from the examples above, that you can get very creative and detailed in the Lists you create, and who you assign to those lists. Your organization is given the opportunity to accommodate any number of hiring scenarios using the options available to you. If you want to further filter employees within each list, you can create Groups or Specialty Classifications as well; and utilize those options when hiring employees back.