mail-addons/mail_outgoing/security/mail_outgoing.xml

<?xml version="1.0" encoding="utf-8"?>
<openerp>
    <data>
        <record model="res.groups" id="group_all_emails">
            <field name="name">all_emails</field>
            <field name="comment">Gets access to all emails. For example to check outgoing emails.</field>
        </record>

        <record model="ir.rule" id="rule_mail_mail_user">
            <field name="name">mail.mail: user</field>
            <field name="model_id" ref="mail.model_mail_mail"/>
            <field name="domain_force">[('author_id', '=', user.partner_id.id)]</field>
            <field name="groups" eval="[(4, ref('base.group_user'))]"/>
            <field name="perm_read" eval="True"/>
            <field name="perm_write" eval="True"/>
            <field name="perm_create" eval="True"/>
            <field name="perm_unlink" eval="False"/>
            <field name="global" eval="False"/>
        </record>

        <record model="ir.rule" id="rule_mail_mail_system">
            <field name="name">mail.mail: system</field>
            <field name="model_id" ref="mail.model_mail_mail"/>
            <field name="domain_force">[(1, '=', 1)]</field>
            <field name="groups" eval="[(4, ref('mail_outgoing.group_all_emails'))]"/>
            <field name="perm_read" eval="True"/>
            <field name="perm_write" eval="True"/>
            <field name="perm_create" eval="True"/>
            <field name="perm_unlink" eval="True"/>
            <field name="global" eval="False"/>
        </record>
    </data>
</openerp>