The documentation about this is very poor but in https://www.odoo.com/documentation/11.0/reference/views.html#calendar show some ways to do parcialy what you need.

lets see..

    <record id="view_l10n_cu_calendar_event_calendar" model="ir.ui.view">
        <field name="name">calendar.event.calendar</field>
        <field name="model">calendar.event</field>
        <field name="inherit_id" ref="calendar.view_calendar_event_calendar"/>
        <field name="arch" type="xml">
            <data>
                   <field name="partner_ids" position="replace" >
                        <field name="partner_ids"/>
                    </field>
            </data>
        </field>
    </record>