Real Modal Dialog with PRISM & RG.PopUp

I would like to achieve a functionality like an DisplayAlert with PRISM and RG.PopUp
PRISM and RG.PopUps works fine together and I know how to deal with NavigatedFrom, NavigatedTo and MessagingCenter to pass Answers back to my ViewModel. But I would like to wait for an answer and move forward afterwards, like in a DisplayAlert. I need just True or False.

if (await DialogService.DisplayAlertAsync("Question", "Yes or no ?, "Yes", "No") == false)
     return;

Something like this ( I made that up):

    var result = await NavigationService.NavigateAsync("PopUpYesNo", navigationParams);
    //now wait for PopUp to close
    if (result == true)
    {
    ...
    }

I can't be the first one looking for that, can I? I googled a lot but found nothing...