pos_select_cashier/views/pos_config_views.xml

<?xml version="1.0"?>
<openerp>
    <data>
    
    	<record id="view_pos_config_form" model="ir.ui.view">
            <field name="name">pos.config.form.view.inherit</field>
            <field name="model">pos.config</field>
            <field name="inherit_id" ref="point_of_sale.view_pos_config_form"/>
            <field name="arch" type="xml">
            	<xpath expr="//sheet/group[last()]" position="after">
            		<group string="Select Cashier" col="1">
            			<group col="4">
                            <field name="required_password" />
                        </group>
                    </group>
            	</xpath>
            </field>
       </record>
    
    </data>
</openerp>