Hello Andrew,
There is no native solution. But using javascript I did this many times. And also explain in the below request.
or
https://roberts.knack.com/farmers#checkuniqueness/
javascript used
$(“#field_281 , #field_282”).live(“change , blur”,function(){
$(“#field_283”).val($(“#field_281”).val()+" “+$(”#field_282").val());
});
Thanks,
Sunny Singla
ssingla1985@gmail.com
+919855089359