whatsapp_web_groups/views/whatsapp_message_views.xml

<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>
        <!-- Extender vista de formulario de WhatsApp Message para agregar campo Many2one -->
        <record id="whatsapp_message_view_form_groups_m2o" model="ir.ui.view">
            <field name="name">whatsapp.message.view.form.groups.m2o</field>
            <field name="model">whatsapp.message</field>
            <field name="inherit_id" ref="whatsapp_web.whatsapp_message_view_form_groups"/>
            <field name="arch" type="xml">
                <!-- Agregar campo Many2one whatsapp_group_id después de recipient_type -->
                <xpath expr="//field[@name='recipient_type']" position="after">
                    <field name="whatsapp_group_id" 
                           invisible="recipient_type != 'group'"
                           required="recipient_type == 'group'"
                           options="{'no_create': True}"/>
                </xpath>
            </field>
        </record>

        <!-- Extender vista de lista de WhatsApp Message -->
        <record id="whatsapp_message_view_tree_groups_m2o" model="ir.ui.view">
            <field name="name">whatsapp.message.view.tree.groups.m2o</field>
            <field name="model">whatsapp.message</field>
            <field name="inherit_id" ref="whatsapp_web.whatsapp_message_view_tree_groups"/>
            <field name="arch" type="xml">
                <!-- Agregar columna whatsapp_group_id -->
                <xpath expr="//field[@name='recipient_type']" position="after">
                    <field name="whatsapp_group_id" optional="hide"/>
                </xpath>
            </field>
        </record>
    </data>
</odoo>