613.1  Joint and several obligations.
  Where two or more persons are bound by contract or by judgment, decree, or statute, whether jointly only, or jointly and severally, or severally only, including the parties to negotiable paper, common orders, and checks, and sureties on the same or separate instruments, or by any liability growing out of the same, the action thereon may, at the plaintiff’s option, be brought against any or all of them. When any of those so bound are dead, the action may be brought against any or all of the survivors, with any or all of the representatives of the decedents, or against any or all such representatives.
[C51, §1681, 1682; R60, §2764; C73, §2550; C97, §3465; C24, 27, 31, 35, 39, §10975; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §613.1]
Separate trials, R.C.P. 1.914