Hey Jordan,
This is actually a little tricky and we actually want to mimic the behavior of Joomla's ACL where deny rule always wins but it seems like this is a much more tedious setup.
Assuming that your user is assigned to 2 user groups, groupA and groupB.
groupA - Allows posting comments
groupB - Disallows posting comments
This user will then be disallowed to post comments. This is at least the behavior of Komento unlike EasyBlog and EasySocial where "allowed rules always wins".
I will discuss with the team on Monday if we should change this behavior by default but it's going to be tricky because since day 1 of Komento, deny always wins. By changing this, site owners who utilizes multiple groups need to start taking note about this as their ACL might be messed up.
What you can do temporarily is to edit the file /components/com_komento/helpers/acl.php and at line 174 locate the codes below:
// This logics prioritizes FALSE
if( (bool) $result[$key] )
{
$result[$key] = $value;
}
// This logics prioritizes TRUE
/*if( !(bool) $result[$key] )
{
$result[$key] = $value;
}*/
Replace it with,
// // This logics prioritizes FALSE
// if( (bool) $result[$key] )
// {
// $result[$key] = $value;
// }
// This logics prioritizes TRUE
if( !(bool) $result[$key] )
{
$result[$key] = $value;
}