@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