Map Dependacy Fields

Map Dependacy Fields

Hi
I was wondering when you will make available the option where we can utilize multi-select fields as a parent field for map dependency.
We have Industry types (more than 20) that some companies over lap.  Rather than having multiple fields I wanted to make this a multi select field and than according to that, have sub-options in the second field. 
We can do a workaround, but it is not pretty.  Im unsure why a Parent field can not be a multi select (would mean we would be using much less fields in the modules which is a win win in my opinion.