A single petition may be filed under this part to free a child, or more than one child if the children are biological siblings, from the custody and control of both parents. A petition filed in accordance with this section may be granted in whole or in part in accordance with the procedures set forth in this chapter. The court shall retain discretion to bifurcate any case in which the petition was filed in accordance with this section, and shall do so whenever it is necessary to protect the interests of a party or a child who is the subject of the proceeding.