Removing duplicates from a Dojo FilteringSelect

Question

Hi,

I'm trying to remove duplicates from a Dojo FilteringSelect without changing the contents of the attached itemFileReadStore data store. I can't seem to find any information on how this is done, if it is indeed possible.

I'm thinking I may have to extend the FilteringSelect Dijit and provide the functionality myself but I'm hoping to not have to.

The reason I'm trying to remove duplicates with the FilteringSelect and not the data store is because I'm using the same data store with three instances of the FitleringSelect, each displaying different values from each row of the store.