confused: Miilee and Rahul's parentage

I have recently started watching this serial and am confused. Don't Miilee and Rahul have the same father, so how come the romantic track?

miilee n rahul don have the same father coz when kamini
(vishals wife) got married to vishal rastogi she was
already pregnant but ramona is vishal's daughter (i
donno how this happened? 😆 ) n miilee's sis

ramona is vishal's daughter the one who always get
angry on rocky n rocky says na ramona baby