NEXUS will more than likely win at SS, and here is how I would handle it from there since Barrett has a shot at the World title I would suggest letting him win it to put him over a little while. Then I would have the rest of the group start losing matches left and right with Barrett being the only one winning matches an using the group to help keep the World title.
In other words I would not break this group but let it break itself up from within, maybe after Survivor Series that is where the group should really start to fall part, and it should start at SS and finish at Survivor Series.