Dropdown mashup select item and after don't include in the same Dropdown
Hello,
I want to select in a dropdown from a list users list ( I have already do this ) , but after add in the second list the user, I want to make sure in the list I can't add second time same user.
I can do this from Mashup or I need to create a service that compare the users from this two list and create another infotable?
Thank you in advance.


