Is it possible to control a parameter type as being single vs. multi-valued based on the value selected in the previous parameter? For example in parameter one the values are: City, State. In Parameter two the values are the respective list of cities or states.

If city is selected in parameter one then the user should only be able to select one city from parameter two. If State is selected in parameter one I want parameter two to be a mult-select.

If this is possible, could it be done via the XML code or would it be possible through any Visual Basic coding?