Use the three-name “et al.” form

Warning²Federal courts, Illinois courts22nd edition only

Where a private communication had more than three participants, the citation names the first three in alphabetical order by last name, with “et al.” for the rest.¹

1. 1R. 18.10.2(a) Audio and video communications; R. 18.10.2(b) Text communications.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.