<search>
                <field name="name"/>
                <field name="marca"/>
                <field name="numero_serie"/>
                <field name="partner_id"/>
                <filter name="active" string="Activas" domain="[('active','=',True)]"/>
                <group expand="0" string="Agrupar por">
                    <filter name="group_marca" string="Marca" context="{'group_by':'marca'}"/>
                    <filter name="group_partner" string="Cliente" context="{'group_by':'partner_id'}"/>
                </group>
            </search>