Adding multiple values in an excel column from a list

Dear all,

I have a excel table where one of the column can contain several values (let's say separated by a ; or , or any other delimiter) that when in editing mode should be picked up from a list of fixed value ... no duplicates are allowed.

Seems that creating that require a little bit of VB and since I am no expert in that was wondering whether someone from that beautiful community could possibly provide a spreadsheet with an example of such 'multiple selections' column. 

If no VB script is required to do that, even better! 
That'd be awesome!

Thks in advance