Brynjolf,
I'm certain that there's some kind of rival Thieves Guild manifesting itself up here in Windhelm. As soon as things settle down with your own, why don't you send someone up here to investigate? I think you'll find I can open quite a few doors for the Guild once you've reestablished yourselves up here. Remember, friends are difficult to come by these days. Don't disappoint me.
Your Friend In The North