Just to give you some background, these Clients have no relation whatsoever with the fields above because nothing has been sold to them in the past, so they are in fact potential Clients. Because of that, if I select a Year or a Partner for example the list would normally show empty. However, I want the list to keep showing no matter what is selected in the fields above.
Please see attached sample file. The 'Red' list box now has the Partners I want to see. The point is that because they are not connected to any sale, whenever I select a Year or anything related to a Partner or a sale, they will disappear. What I'm trying to achieve is first of all for the list to keep visible regardless of the selections and then to grow with the other Clients currently in 'Green' and 'Yellow' that will become with 0 Year if I make a particular selection - i.e. a specific Year during which they didn't buy anything, a Partner they were never served from, etc.