Wis. Stat. § 779.09: Foreclosure of lien; procedure; parties.

In the foreclosure of liens mentioned in s. 779.01, ch. 846 shall control as far as applicable unless otherwise provided in this subchapter. All persons having filed claims for liens under s. 779.01 may join as plaintiffs, and if any do not join they may be made defendants. All persons having liens subsequent to such lien may be joined as defendants. If any person who is a proper party is not a party to the action the person may, at any time before judgment, be made a defendant, and any person who after the commencement of the action obtains a lien or becomes a purchaser may, at any time before judgment, be made a defendant.