Remove duplicates from Concatenated Child to Parent Field - Involves Javascript

I see underscore in there so you can use that by using this. Just pass your array of words through this before sending to the concat field. I haven't used underscore a lot so Dan may chime in with a way better answer as always :P
http://underscorejs.org/#uniq

_.uniq(data);


Another examle

_.uniq([1, 2, 1, 4, 1, 3]); 

=> [1, 2, 4, 3]

For sorting you can then pass it through something like this _.iteratee(value, [context])