Section 601. Joinder of claims

(a) The plaintiff in a complaint or the
  defendant in an answer setting forth a counterclaim or  cross-claim  may
  join  as  many claims as he may have against an adverse party. There may
  be like joinder of claims when there are multiple parties.
    (b) Two or more plaintiffs may join no more than five  claims  in  any
  one  action  or  proceeding  against  the  same defendant arising out of
  separate consumer credit transactions, provided that the plaintiffs  are
  represented by the same attorney.