NEW TEMPLATE

<f:layout name="Default" />
<f:section name="Title">New father</f:section>
<f:section name="Content">

    <f:form action="create" objectName="newFathers">
        <label for="name">Father 01</label>
        <f:form.textfield property="0.name" />
        <label for="nameson">Sons</label>
        <f:form.textfield property="0.sons.0.name" id="sonInput00" /><br>
        <f:form.textfield property="0.sons.1.name" id="sonInput01" /><br>
        <f:form.textfield property="0.sons.2.name" id="sonInput02" /><br>
        <br>
        <label for="name">Father 02</label>
        <f:form.textfield property="1.name" />
        <label for="nameson">Sons</label>
        <f:form.textfield property="1.sons.0.name" id="sonInput10" />
        <f:form.textfield property="1.sons.1.name" id="sonInput11" />
        <f:form.textfield property="1.sons.2.name" id="sonInput12" />
        <f:form.submit value="Create" />
    </f:form>

</f:section>


Create Action
/**
     * Adds the given new array of father objects to the father repository
     *
     * @param array<\Mario\Basic\Domain\Model\Father> $newFathers An array of new fathers to add
     * @return void
     */
    public function createAction(array $newFathers) {
        foreach ($newFathers as $father) {
            $this->fatherRepository->add($father);
        }
    }