It is narrated from Sayyiduna Sahl bin Sa’d Sa’idi (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: Whoever, after performing one prayer, waits for the next prayer in the same gathering, he is considered to be in prayer.
Hadith Referenceالفتح الربانی / كتاب الصلاة / 1044