public class EntityContainer
    {
        public GameWorld GW;
        public Dictionary<int, BaseEntity> All;
        public Dictionary<Segment, List<BaseEntity>> BySegment;
        public Dictionary<EntitySchematic, List<BaseEntity>> BySchematic;

        public EntityContainer(GameWorld parent)
        {
            GW = parent;
            All = new Dictionary<int, BaseEntity>();
            BySegment = new Dictionary<Segment, List<BaseEntity>>();
            foreach (Segment segment in GameWorld.Segments)
            {
                BySegment.Add(segment, new List<BaseEntity>());
            }

            BySchematic = new Dictionary<EntitySchematic, List<BaseEntity>>();
            BySchematic.Add(EntitySchematics.Tree, new List<BaseEntity>());
        }

        public void AddEntitiy(BaseEntity entity)
        {
            All.Add(entity.ID, entity);
            BySegment[entity.GetSegment()].Add(entity);
            BySchematic[entity.Schematic].Add(entity);
        }

        public void RemoveEntitiy(BaseEntity entity)
        {
            All.Remove(entity);
            BySegment[entity.GetSegment()].Remove(entity);
            BySchematic[entity.Schematic].Remove(entity);
        }
    }