Maimonides' opinion on the equal side

There is a difference in the essence of the equal side. There are two main opinions. The Rosh and the opinion of the great ones in Rosh
It seems that the Rosh believes that once there is a father from whom the main learning is derived, he is considered the same as the father himself, but the opinion of the elders says that the exemptions of the two fathers being learned are learned.
The Tur and the Shulchan Arbiter are verses like the Rosh, but I was unable to understand the Maimonides' opinion on the subject…. Can you help?