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Continue to ChatMention multiple users in the chatter post using Apex https://sfdclesson.com/2021/05/15/mention-multiple-users-in-the-chatter-post-using-apex/
Mention multiple users in the chatter post using Apex https://sfdclesson.com/2021/05/15/mention-multiple-users-in-the-chatter-post-using-apex/