Flex :: Data Fetching From The Server?

I have a Flex-based client app which "talks" to the back-end through BlazeDS. In one of my use cases there will be a so called "Photo Wall" view, which will present a number of the most recent photos, submitted from people and for locations the user is following (Facebook-like).

The thing is, the data in this photo wall has to be filtered by "All", meaning no filter, "Friends", meaning friends that the user is following, and "Locations", meaning locations the user is following. If I get data from the server only once (when the ALL filter is selected by default), I will store it locally, and the next time a user clicks on a filter, this local collection will be filtered locally. The problem is that I can't predict how many of all recent photos are coming from friends, and how many from locations, thus I may end up with a page that shows only one photo, where a minimum of 5 photos should always be present. I clearly don't want to deal with partial fetching and stuff like that.

The other way is making two separate requests to the server initially, one to get a collection of recent photos from friends, and one for locations. Thus I will make sure I have the bare minimum of photos for the filtered pages. When data arrives, the client will merge those two collections, sort by date, and voila there is the "ALL" collection (of course, repeating photos will have to be pruned while merging)Third, making this same thing down at the server level, by making two separate queries and then merging them.