multi_store_partner/security/multi_store_security.xml

<?xml version="1.0"?>
<openerp>
    <data noupdate="1">
        <record id="res_partner_store_rule" model="ir.rule">
            <field name="name">Res Partner multi-store</field>
            <field name="model_id" ref="base.model_res_partner"/>
            <field name="global" eval="True"/>
            <field name="domain_force">['|',('store_id','=',False),('store_id','child_of',[user.store_id.id])]</field>
        </record>
    </data>
</openerp>