Is it permissible for me to pray with the congregation of 'Isha' intending Maghrib, and then wait for another congregation to pray 'Isha' with them?

Question:
May Allah reward you. The honorable scholar says: I prayed, and I was traveling. I prayed Maghrib with a congregation that was praying 'Isha' in the city. I intentionally delayed because I was alone, and in the delay I would catch the congregation for the 'Isha' prayer. Then, after I prayed with them, I waited for another congregation to make up 'Isha', but no one came. So I delayed 'Isha' until about ten o'clock. Is my action correct?

Answer:
Your action is not correct. Your prayer is valid, if Allah wills, but you made a mistake in this conduct.
You should have prayed Maghrib first. You should have hastened to pray Maghrib, then prayed 'Isha' with the congregation. This is what you should have done: pray Maghrib first, then pray 'Isha' with the congregation, even if you only caught the end of the prayer. As for entering with them intending Maghrib,
while they were praying 'Isha', and then waiting for 'Isha' hoping to catch a second congregation, and no one came to you, and you delayed the 'Isha' prayer. Your prayer was valid, if Allah wills, in both cases. But if you had prayed Maghrib first, then prayed 'Isha' with the congregation, or whatever part of it you caught, that would have been better and more excellent. Yes.