Create Percentage & Absolute Thresholds for Proxy Vote Custom Fields

We have implemented a custom field on the proxy vote of Customer Value using a predefined choice list of 5 options (scale Low - Top priority). We'd like to be able to cap the absolute count number of ideas that can be assigned a value of Top or High priority as well as a percentage cap. i.e. an individual organization can only have the lower of 3 absolute count Top priority ideas or 15% Top priority ideas.