@MaxonL16591286Unfortunately, When rules do not provide a direct function to check all entries of a Page Group like they do for a Page List ​​​​​​. Where are you trying to use this when rule? You could perhaps use a Data Transform before the when rule initiates to iterate over each entry in the Page Group and then use that property in the when rule.

For Each Page in <PageGroup> 
   If (<Condition>)
      Set .FlagForCondition = true
      Exit Iteration

Then, in the When rule, simply check if .FlagForCondition = true