I have a one2many field inside form, in this field i want to group by two field so i do some search i found that in odoo we can't group by fields in tree view inside a form, so i decided to add button that return tree view of model (one2many field), but until now i con't return tree view with group by fields any advices.

my code :

def display_offers(self):
    search_view_id = self.env.ref('module_name.eligibility_result_filter').id
    tree_view_id = self.env.ref('module_name.eligibility_result_tree').ids
    form_view_id = self.env.ref('module_name.eligibility_result_form').ids
    return {
        'name': _('Display offers'),
        'view_mode': 'tree',
        'res_model': 'model.model',
        'domain': str([('id', 'in', self.one2many_field.ids)]),
        'context': {'search_default_operator': 1, 'search_default_technology': 1},
        'search_view_id': search_view_id,
        'views': [[tree_view_id, 'tree'], [form_view_id, 'form']],
        'type': 'ir.actions.act_window',
        'target': 'current',

} 

<record id="eligibility_result_filter" model="ir.ui.view">
    <field name="name">model.model.filter</field>
    <field name="model">model.model</field>
    <field name="arch" type="xml">
        <search string="offers">
            <group expand="1" string="Group By...">
                <filter name="Oper" string="Operator" domain="[]" context="{'group_by':'operator'}"/>
                <filter name="tech" string="Technology" domain="[]" context="{'group_by':'technology'}"/>
            </group>
        </search>
    </field>
</record>