I would always communicate with their attorneys.
If I was going to sue someone and I knew they are represented I'd be sending everything to his or her attention. There are some exceptions too, such as some agreements state that the creditor must be notified in case of election (arbitration), but that's a rarity.
Now before biting off a big chunk of flesh, you want to make sure you don't bite more than you can chew.
I see that your experience in legal manner (s) is limited (from your posting) and based on my observation what exactly did they violate? Beside filing suit after they received your "election letter".