A partial summary judgment becomes final and appealable when the trial court signs an order severing into a separate case the parties and claims addressed. Mafrige v. Ross, 866 S.W.2d 590, 592 (Tex. 1993). Texas Rule of Civil Procedure 41 provides that "any claim against a party may be severed and proceeded with separately." TEX. R. CIV. P. 41. A trial court has broad discretion in the matter of severance and consolidation of causes. Guaranty Fed. Sav. Bank v. Horseshoe Operating Co., 793 S.W.2d 652, 658 (Tex. 1990). The standard of review for determining whether a trial court erred in ordering a severance is abuse of discretion. Id. The reasons undergirding a proper grant of severance "are to do justice, avoid prejudice and further convenience." Id. Severance is proper if: (1) the controversy involves more than one cause of action; (2) the severed claim is one that would be the proper subject of a lawsuit if independently asserted; and (3) the severed claim is not so interwoven with the remaining action that they involve the same facts and issues. Id.