On Dec 26, 4:43 am, Robert Klemme <shortcut... / googlemail.com> wrote: > Also it seems, the spec is not yet fully clear > (to you). That was my thought. It seems the OP wants treat two different streams as the same kind of data (but keyed on different values). I can think of a way to abstract this, but it just "feels" wrong. Seems like this kind of thing is best suited to a DB/ORM mapping rather than trying to do it by hand. Regards, Joordan