Misjoinder of parties is not ground for dismissal of an action. Parties may be dropped or added by order of the court on motion of any party or of its own initiative at any stage of the action and on such terms as are just. Any claim against a party may be severed and proceeded with separately. In determining whether to add or drop parties under this section, the court shall consider if in the interest of justice such action provides a fair and convenient forum for all parties.