Can you find a solution, i need the same?

Also, with something like this It's possible to hide the buttons from an specific user groups. This example hide the buttom edit in the Invoice Form. The users of the groups have write privileges only for posting on the messages an communication history but not the fields of the invoices.

   <record model="ir.ui.view" id="YOURNEWVIEWID">
         <field name="name">account.invoice.form</field>       
         <field name="model">account.invoice</field>       
         <field name="inherit_id" ref="PARENTFORMID" />       
         <field name="groups_id" eval="[(6,0, [ref('YOURSPECIFICGROUP')])]" />       
         <field name="arch" type="xml">          
            <xpath expr="//form[@string='Invoice']" position="attributes">
                <attribute name="edit">false</attribute>       
            </xpath>       
         </field>   
    </record>
To hide a page it is similar, the difference will be in the xpath section
   <record model="ir.ui.view" id="YOURNEWVIEWID">         
        <field name="name">account.invoice.form</field>                
        <field name="model">account.invoice</field>                
        <field name="inherit_id" ref="PARENTFORMID" />                
        <field name="groups_id" eval="[(6,0, [ref('YOURSPECIFICGROUP')])]" />                
        <field name="arch" type="xml">                      
            <xpath expr="//page[@string='Invoice Lines']" position="replace">     
            <!-- nothing here-->
            </xpath> 
            <!-- OR -->
            <xpath expr="//page[@string='Invoice Lines']" position="attributes">     
               <attribute name="invisible">True</attribute>
            </xpath>             
        </field>       
    </record>