db={domains:[{"_id":ObjectId("64fb3cf27f6c107e984015a1"),"domain":"green","portfolioId":ObjectId("650ecb80507561a33ce927a1")},{"_id":ObjectId("64fb3cf27f6c107e984015a2"),"domain":"blue","portfolioId":ObjectId("650ecb80507561a33ce927a2")}],portfolios:[{"_id":ObjectId("650ecb80507561a33ce927a1"),"portfolioName":"first","userIds":ObjectId("650ecb80507561a33ce927a3")},{"_id":ObjectId("650ecb80507561a33ce927a2"),"portfolioName":"second","userIds":ObjectId("650ecb80507561a33ce927a4")}],users:[{"_id":ObjectId("650ecb80507561a33ce927a3"),"emailAddress":"bob@gmail.com"},{"_id":ObjectId("650ecb80507561a33ce927a4"),"emailAddress":"sally@gmail.com"},{"_id":ObjectId("650ecb80507561a33ce927a5"),"emailAddress":"paul@yahoo.com"}]}

db.domains.aggregate([{"$lookup":{"from":"portfolios","localField":"portfolioId","foreignField":"_id","as":"portfolioId"}},{"$lookup":{"from":"users","localField":"portfolioId.userIds","foreignField":"_id","as":"userIds"}},{"$match":{"portfolioId.userIds":ObjectId("650ecb80507561a33ce927a3")}}])