I am just guessing, but perhaps when you filed suit against the defendant, the defendant may have brought into the suit other parties because of contractual relationships it may have had with those other parties. That suit, called a "3rd party action" can be a fight to determine the split of responsibility between the other parties. Wars like that, between several insurance companies, can go on for years, because they want it to set a precedent for other contract wars that they have between themselves.
Answered on Nov 21st, 2013 at 1:51 PM