Search on one field based on other fields

Hi,
I'm wandering if this is possible and how.
I have article with 3 possibles addresses for a person.
My fields are address1, Postcode1, City1, address2, Postcode2, City2, address3, Postcode3, City3.

I want to have a Flexi search form (the search module) but to have a dropbox with all the cities.
So how to have only one dropdown list with all the content of the fields city1, city2, city3.
Note this : the fields for the cities are allready lists (i have typed all the cities to prevent error of typing).

Thanks for the help

no you need to use on field like city
but you can use multivalue option in field to allow user to add more value and you can block number of submission to 3 values

Hi Micker,
Your solution is not relevant for this question, sorry
As i use différent fields and address, i cannot use multi values fields, especially for different addresses which needs to be separated (you cannot type in a field 3 differents addresses or it's going to be difficult for people to understand what are the addresses to read...).

but you can use groupfield not ?

Ok, let think different (no an advert !!)

How to populate a field with 3 others fields ?
For example, i have the fields X, Y, Z with single value choosen in a dropdown menu.
How to put the value in X, Y, Z in a fourth field AAA with these 3 values ? Is there a possibility for this ?
Thanks !

Hello

there is no option to combine multiple fields into a single filter