In instances where there is not a joint custody arrangement or a move is allowed in the custody agreement, the noncustodial parent must show that the intended move would be detrimental to his relations with the children. If the noncustodial parent is able to show a move will be detrimental, the court will then determine whether a change of custody is in the best interests of the children.
You will have to notify the Father's of the move and if they object you will have to go to court.
California Family Code section 7501 provides, "A parent entitled to the custody of a child has a right to change the residence of the child, subject to the power of the court to restrain a removal that would prejudice the rights or welfare of the child."
Although this statute appears to be straightforward, the interpretation of it has not been. The right of a custodial parent to move away with a minor child when doing so would adversely affect the noncustodial parent's visitation has been fought vigorously in the Courts.
Regarding notice of in a relocation or move away case, California Family Code Section 3024 states, "In making an order for custody, if the court does not consider it inappropriate, the court may specify that a parent shall notify the other parent if the parent plans to change the residence of the child for more than 30 days, unless there is prior written agreement to the removal. The notice shall be given before the contemplated move, by mail, return receipt requested, postage prepaid, to the last known address of the parent to be notified. A copy of the notice shall also be sent to that parent's counsel of record. To the extent feasible, the notice shall be provided within a minimum of 45 days before the proposed change of residence so as to allow time for mediation of a new agreement concerning custody. This section does not affect orders made before January 1, 1989."
Your best bet would be to offer a plan that the Father's would accept, and if they agree you can move.