Drop Down Boxes

I am trying to creat an organization chart using the SmartArt tools. My
problem is that the chart entries are Position Title based using the Incident
Command System titles (i.e. Incident Commander instead of CEO, etc). Since
any of several predefined people can hold any given position, I am trying to
find a way to put in somethng like a drop-down box in each postion block
where I will have the list of people who would normally fill that position as
well as including an "other" option. I am new to using SmartArt and would
appreciate any help on this since I cannot find anything in Microsoft's help
areas.

Thanks