To my knowledge, Tableau does not have this kind of functionality. I will present you two alternatives.
1) Using parameters to select this. Check the attached workbook for an example.
2) Tableau 8 Server contains a mobile authoring feature that will allow people to open an interface that looks very similar to Tableau Desktop. Perhaps these users could use this feature to drag and drop any dimensions they want onto that visualization.
No workbook is attached.
Can you check again.