On Jun 10, 2019, at 12:53 PM, Ben Coman <btc@openinworld.com> wrote:If you are keeping your design purely in the object-oriented domain,you might try Mutual Friends... https://pdfs.semanticscholar.org/348f/e4ecff3c23f3709bb88e7e60379905a3b930.pdfalthough I've not enough experience with it to know if its the best way.