Hi, basically, model the entire EPD as separate life cycle stages, each stage is one product system (or, each stage that you need to distinguish, so A1-A3 can be lumped together e.g.), and then make one "super" product system where the entirel life cycle is reflected, which contains these product stage product system. In D, model the credits from the system. You can couple flow amounts across product systems using parameters. We plan to have a webinar and more documentation about this once finally finally openLCA 2 is out - thank you!