Something

        //Pull out highest priority season.
        IList seasons = this.edSeasonsEditor.Product.ProductSeasons;
        //No good doing stuff if there's no seasons.
        if (seasons.Count == 0) return;

        ProductSeason highestSeason = seasons[0];
        ProductSeasonList results;
        //Do projections
        foreach(Season list in seasons)
        {
            if(results==null) 
           { 
                  results = new ProductSeasonList(highestSeason);
           } else
{ results = results.ProjectOnto(list);
}
        }
        //Save results to flat periods table