The ruling on waiting for the second congregation for one who joins the prayer late

Question:
Honorable Shaykh, he says: Some scholars say that if one who joins the prayer late catches up with the congregation while they are in the last part of the prayer, and he hopes for another congregation, he should wait for the other congregation, so that he is in the prayer of those who started earlier. This appears, on its surface, to contradict the saying of the Prophet (peace and blessings be upon him) , and the matter is obligatory on its apparent meaning. I hope you will clarify this, because it has confused me.

Answer:
Yes, this is confusing, but he did not leave joining the imam except for something better than joining him.
That is because he left joining him in order to obtain the prayer in congregation, since the correct of the scholars' opinions is that the congregation is not achieved except by catching up with one unit of prayer. If he does not catch up with one unit, he misses the congregation, and the congregation is obligatory if it is possible.
Joining the imam is a recommended practice, so he left it for the sake of an obligation. This is if he knows that there are people behind him who will attend; then he waits and prays with them in congregation. But if he does not know and no one has informed him that anyone will come, he does not neglect the rest of the prayer; he joins the imam.