I have set up some Private Social Groups where only administrators can add users. On the group page, there is a link that allows users to click a "Leave Group" link. Is there a way to disable or remove this link? My users are using this link to return to the groups page and inadvertently leaving the group, forcing us to re-add them to the group.

You could use some javascript like below:

$(function() {

$("div.ModSocialGroupsC a:contains('Leave Group')").hide();

});