I don't know much about quakerism, but the answer seems to be a rude "no", I'm sorry. As soon as you enter into Zoroastrianism, you can choose your branch, but you cannot have another religion. That would be cheating with God. Imagine: if two dogmas differ, which one should you choose? It's like when you convert to Christianity, you can choose to be either a Protestant, or a Greek Orthodox or a Catholic, but you cannot choose to be a Catholic AND a Jew or a Protestant AND a buddhist. To me, that makes sense!