<data priority="50">
  <xpath expr="(//address[@t-field='o.partner_id'])[1]" position="before">  
     <strong class="d-block mt-3">Billing address</strong>
  </xpath>
  <xpath expr="(//address[@t-field='o.partner_id'])[2]" position="before">  
     <strong class="d-block mt-3">Billing address</strong>
  </xpath>
  <xpath expr="(//address[@t-field='o.partner_id'])[3]" position="before">  
     <strong class="d-block mt-3">Billing address</strong>
  </xpath>
</data>