Right-clicking on any message or folder in the Message Levels or Rule Groups panel allows you to create a diagnostics display filter. You can select Show Only, so that only the diagnostics for that message or folder are displayed, Hide so that the diagnostics for that message or folder are not displayed, or Show to redisplay diagnostics that are currently hidden. By a combination of these options, you could, for example, choose to show all instances of a single message for a particular component and Rule Group.
Perforce QAC Analysis Explorer: Files Panel
Perforce QAC Analysis Explorer: Rule Groups Panel
Perforce QAC Analysis Explorer: Message Levels Panel
Perforce QAC Analysis Results Panel
Perforce QAC Project Analysis Errors Panel
Options: Analysis Settings Dialog
Options: Perforce QAC Logs Dialog
Options: Perforce QAC Options Dialog