(a) These rules shall govern all actions for legal and physical custody, including original actions, modification petitions, contempt petitions, and registration of foreign decrees. The rules shall be interpreted as supplementing the Rules of Civil Procedure governing custody actions, Pa.R.C.P. 1915.1 et seq.(b) If a claim for legal and physical custody is raised during the course of an action for support, a party shall file a separate action for legal and physical custody with the Prothonotary.