It was suggested to me recently by a Dominican Father that one reason why there is so much opposition to the doctrine of Limbo (the limbo of unbaptised souls of persons dying before the age of reason) is not so much the idea that people might fail to reach the beatific vision without any personal fault but simply the fact of the separation it implies between (say) parents and children. In part this objection probably arises from  too naturalistic a conception of heaven, as if the main point of the life to come was to have a re-union of all the people we have known on earth. But maybe there is something more to it. The blessed and those in limbo (Limbonians?) after all share the same nature, even though for the blessed this nature is divinised, and members of each group voluntarily direct themselves to the same Common Good, God loved above all else, even though the love by which the blessed love God infinitely surpasses that of the others. So is it conceivable that these two groups might share some kind of common life? Could there be some kind of communication between them? Maritain in his essay Idees Eschatologiques speculates on angels visiting those in limbo and telling them things about heaven and Jesus. Maybe the saints could do the same.