Untitled

window.ArtistCollection = Backbone.Collection.extend({
    initialize: function(models, ops) {
        if(ops.updater) {
            this.updater = ops.updates;
            this.updater.bind('update', _.bind(this.onUpdater, this));
        }
    },

    onUpdater: function(response) {
        // send the updates to the correct model
        // id. Maybe even as a parse args if its
        // in full model json
    }
});

// then just
var popArtists = new ArtistCollection(null, {updater: window.fayeClient});
var trackedArtists = new ArtistCollection(null, {updater: window.fayeClient});

// if this is a common pattern, you could wrap it into a new Backbone base