Ite Ad Thomam: The Principle of Predilection: "Nothing would be greater if God did not will it more good."
The "inequality" of God's love for us can be reflected in the order of charity - we should love those who are closer to God more than those who are not (i.e. wish them a greater good). (As opposed to the intensity of our love.)
Still, Aquinas touches upon how charity can command acts of other forms of friendship.
"Moreover there is yet another reason for which, out of charity, we love more those who are more nearly connected with us, since we love them in more ways. For, towards those who are not connected with us we have no other friendship than charity, whereas for those who are connected with us, we have certain other friendships, according to the way in which they are connected. Now since the good on which every other friendship of the virtuous is based, is directed, as to its end, to the good on which charity is based, it follows that charity commands each act of another friendship, even as the art which is about the end commands the art which is about the means. Consequently this very act of loving someone because he is akin or connected with us, or because he is a fellow-countryman or for any like reason that is referable to the end of charity, can be commanded by charity, so that, out of charity both eliciting and commanding, we love in more ways those who are more nearly connected with us."