1. Define your field as usual, but don't close the tag:

<field name="child_ids"> 

2. Write the view definition(s) into the tag:

<tree>
    <field name="name" />
    <field name="email" />
    <field name="phone" />
</tree>
<form>
    <group>
        <field name="name" />
        <field name="function" />
    </group>
</form>

3. Close the tag:

</field>