Dynamically change the label of the multi-select form

Hello,
I've added 3 separate multiselect (MS) to a particular page, but I need to be able to change the label for each multiselect form based on which node the multipselect values are referenced. For example, first MS for is referencing a node of companies and I want to change the label above the "available options" list to "something else" and the label above the "selected options" to "something else selected". Right below this MS, I have a 2nd MS which is referencing a different node bringing in values of products, and I want the label for this "available option" to be something different than the one I've listed above. Please see screenshot to get a better idea. Any help would be greatly appreciated.

Thanks in advance.