C.R.S. § 14-5-204

(a) A tribunal of this state may exercise jurisdiction to establish a support order if the petition or comparable pleading is filed after a pleading is filed in another state or a foreign country only if: (1) The petition or comparable pleading in this state is filed before the expiration of the time allowed in the other state or the foreign country for filing a responsive pleading challenging the exercise of jurisdiction by the other state or the foreign country; (2) The contesting party timely challenges the exercise of jurisdiction in the other state or the foreign country; and (3) If relevant, this state is the home state of the child. (b) A tribunal of this state may not exercise jurisdiction to establish a support order if the petition or comparable pleading is filed before a petition or comparable pleading is filed in another state or a foreign country if: (1) The petition or comparable pleading in the other state or foreign country is filed before the expiration of the time allowed in this state for filing a responsive pleading challenging the exercise of jurisdiction by this state; (2) The contesting party timely challenges the exercise of jurisdiction in this state; and (3) If relevant, the other state or foreign country is the home state of the child.