Tex. R. Civ. P. 97

(a) Compulsory Counterclaims. A pleading shall state as a counterclaim any claim within

the jurisdiction of the court, not the subject of a pending action, which at the time of filing

the pleading the pleader has against any opposing party, if it arises out of the transaction

or occurrence that is the subject matter of the opposing party's claim and does not require

for its adjudication the presence of third parties of whom the court cannot acquire

jurisdiction; provided, however, that a judgment based upon a settlement or compromise

of a claim of one party to the transaction or occurrence prior to a disposition on the merits

shall not operate as a bar to the continuation or assertion of the claims of any other party

to the transaction or occurrence unless the latter has consented in writing that said judgment

shall operate as a bar.

(b) Permissive Counterclaims. A pleading may state as a counterclaim any claim against an

opposing party whether or not arising out of the transaction or occurrence that is the subject

matter of the opposing party's claim.

(c) Counterclaim Exceeding Opposing Claim. A counterclaim may or may not diminish or

defeat the recovery sought by the opposing party. It may claim relief exceeding in amount

or different in kind from that sought in the pleading of the opposing party, so long as the

subject matter is within the jurisdiction of the court.

(d) Counterclaim Maturing or Acquired After Pleading. A claim which either matured or

was acquired by the pleader after filing his pleading may be presented as a counterclaim

by amended pleading.

(e) Cross-Claim Against Co-Party. A pleading may state as a cross-claim any claim by one

party against a co-party arising out of the transaction or occurrence that is the subject matter

either of the original action or of a counterclaim therein. Such cross-claim may include a

claim that the party against whom it is asserted is or may be liable to the cross-claimant for

all or part of a claim asserted in the action against the cross-claimant.

(f) Additional Parties. Persons other than those made parties to the original action may be

made parties to a third party action, counterclaim or cross-claim in accordance with the

provisions of Rules 38, 39 and 40.

(g) Tort shall not be the subject of set-off or counterclaim against a contractual demand nor a

contractual demand against tort unless it arises out of or is incident to or is connected with

same.

(h) Separate Trials; Separate Judgments. If the court orders separate trials as provided in

Rule 174, judgment on a counterclaim or cross-claim may be rendered when the court has

jurisdiction so to do, even if the claims of the opposing party have been dismissed or

otherwise disposed of.