<?xml version="1.0"?>
<search>
                <field name="partner_id"/>
                <field name="project_id"/>
                <group expand="0" string="Group By">
                    <filter name="project" string="Project" context="{'group_by': 'project_id'}"/>
                    <filter name="collaborator" string="Collaborator" context="{'group_by': 'partner_id'}"/>
                </group>
            </search>
        