there is no such option for multiple match. lookup returns null when there is no match. And if you expect null for multiple match as well, then how do you differentiate what is un-matched ones and what is multi match.
Solution i could think of is , after lookup add expression and compare the keys with previous record, if same set the required col to null
or if sql override is supported in the lookup, try to come up with a sql that would merge 2 records into 1 and give null as return values
Hi Nihar ,
Hope the above suggestion is working for you.