Access Query Criteria (1 Viewer)

I have a table that has two fields one called Town_Name and one called Post_Town.

I want to concatenate the two together and I am using
New_Field:[Town_Name]&", "&[Post_town]&", "&[Postcode]

Now this works OK and I get
WINCHESTER, WINCHESTER, SO23 9LJ however in the two fields I have the situation where some of the records are the same in both fields ie. WINCHESTER or ALRESFORD and I would like to only show in the concatenation one of the entries and the result being
WINCHESTER, SO23 9LJ

Any help would be gratefully received

You can use an IIf() to test the two fields against each other, and return the appropriate fields based on that test.