Metadata example:

(assume crm is Odoo, and crm_tag crm

Module "crm"

<view id='partner_view'>

    ....

    <field name='name'/>

</view>

Module "crm_tag"

depends: crm

<view id='partner_tag_view'>

    <field name='inherit_id' ref='crm.partner_view'/>

    ....

    <field name='name' position='after'>

        <field name='partner_tag_id'/>

        <field name='partner_tag_special' invisible='1'/>

    </field>

</view>

Module "crm_overdue"

depends: crm

<view id='partner_overdue_view'>

    <field name='inherit_id' ref='crm.partner_view'/>

    ....

    <field name='name' position='after'>

        <field name='overdue_warning'/>

     </field>

</view>

Now, if I want to bridge the two modules and use elements of both views:

Module "crm_tag_overdue"

depends: crm_tag, crm_overdue

<view id='partner_xxx_view'>

    <field name='inherit_id' ref='????'/>

    ....

    <field name='overdue_warning' position='attributes'>

        <attribute name='attrs'>{'invisible': [('partner_tag_special', '=', True)]}</attribute>

    </field>

</view>

If I inherit from crm_tag.partner_tag_view, then overdue_warning will not be defined.
If I inherit from crm_overdue.partner_overdue_view, then partner_tag_special will not be defined?