multi selection - Ways to select a group or individual items from fair sized list

Let say I have a list of 20 Employees of a company and they are grouped into a handful (5) Departments. I need to select one or more Employees or Departments. What are some approaches to do this?

Auto suggestion / Typeahead type field comes to mind, but I haven't really seen any examples where they show grouped data and allow the group to be selected.

Answer

I ended up asking the dev to build a multi-select typeahead.

We put in icons to depict the different level in the hierarchy. If the group is selected, the associated icon is shown so the user knows the group is selected.