四分律比丘含注戒本 2.313

2.313

若無別眾食緣，當起白言：「我於此別眾食中無因緣，欲求出。」若餘人無緣，亦聽使出。若二人、三人，隨意食。四人若過，應分作二部，更互入食。若有別眾因緣欲入，尋起白言：「我有別眾食因緣，欲求入。」佛言：「當隨上座次入。」有緣不說，吉。隨別眾食，咽咽結墮。尼同犯。不犯者：如上具列開緣；若二人、三人；更互食；若說有因緣去者，開。

(If one does not have a reason for eating as a dissentient group, one should stand up and announce, 'I have no reason for this meal as a dissentient group; I wish to seek to leave.' If others have no reason, they are also permitted to leave. If there are two or three persons, they may eat at will. If four persons or more, they should divide into two groups and take turns entering to eat. If one has a reason for a dissentient group and wishes to enter, one immediately stands up and announces, 'I have a reason for a meal as a dissentient group; I wish to seek to enter.' The Buddha said: 'One should enter according to seniority of elder monks.' If having a reason one does not state it, it is a duṣkṛta. Conforming to eating as a dissentient group, with each swallow a falling [offence] is incurred. Bhikṣuṇīs share the offence. As for non-offences: the exceptions listed in detail above; if there are two or three persons; eating in turns; or if having stated that one has a reason, one leaves—these are permitted.)