Go to Cross-Sell page from Add to Cart

product-form.liquid

<button type="submit" name="add" class="action_button add_to_cart {% if show_payment_button %} action_button--secondary {% endif %}" data-label={{ add_to_cart_label | json }}>

  {% if product.tags contains 'Cross-Sell-A' %}
    <input type="hidden" name="return_to" value="/pages/cross-sell-a" />
  {% endif %}
  {% if product.tags contains 'Cross-Sell-B' %}
    <input type="hidden" name="return_to" value="/pages/cross-sell-b" />
  {% endif %}           

  <span class="text">{{ add_to_cart_label }}</span>
  <svg x="0px" y="0px" width="32px" height="32px" viewBox="0 0 32 32" class="checkmark">
    <path fill="none" stroke-width="2" stroke-linecap="square" stroke-miterlimit="10" d="M9,17l3.9,3.9c0.1,0.1,0.2,0.1,0.3,0L23,11"/>
  </svg>
</button>