A. Nothing contained in this law shall deprive any other court of the concurrent jurisdiction to determine the custody of children upon a writ of habeas corpus under the law, or to determine the custody, guardianship, visitation or support of children when such custody, guardianship, visitation or support is incidental to the determination of causes pending in such courts, nor deprive a circuit court of jurisdiction to determine spousal support in a suit for separate maintenance. However, when a suit for divorce has been filed in a circuit court, in which the custody, guardianship, visitation or support of children of the parties or spousal support is raised by the pleadings and a hearing, including a pendente lite hearing, is set by the circuit court on any such issue for a date certain or placed on a motions docket within 21 days of the filing, though such hearing itself may occur after such 21-day period, the juvenile and domestic relations district courts shall be divested of the right to enter any further decrees or orders to determine custody, guardianship, visitation or support when raised for such hearing and such matters shall be determined by the circuit court unless both parties agreed to a referral to the juvenile court. In any case in which the jurisdiction of the juvenile and domestic relations district court has been divested pursuant to this section and no final support order has been entered, any award for child support or spousal support in the circuit court shall be retroactive to the date on which the proceeding was commenced by the filing of the action in the juvenile and domestic relations district court, provided that the petitioner exercised due diligence in the service of the respondent. Nothing in this section shall deprive a circuit court of the authority to refer any such case to a commissioner for a hearing or shall deprive the juvenile and domestic relations district courts of the jurisdiction to enforce its valid orders prior to the entry of a conflicting order of any circuit court for any period during which the order was in effect or to temporarily place a child in the custody of any person when that child has been adjudicated abused, neglected, in need of services or delinquent subsequent to the order of any circuit court.