Perhaps you are referring to the practice in the Shia community of combining the Zuhr and Asr prayers and the Maghrib with Isha prayers.

This is considered permitted on account of abundant evidence in the Islamic sources that the Prophet (s) had combined these prayers without any special reason.

You can read more about this topic here:

https://www.al-islam.org/articles/laws-and-practices-why-do-shiah-combine-prayers