rails fields_for array of number_field must be of different values

Question

I'm working on a ruby on rails app, where I have a model called categories with a field called "order_point", even though the "order_point" field shouldn't be of unique (different) value per record,

I want to create a form where I update multiple records's order_point attribute, and I want to make the form accept only the entered values of order_point, only if the the values are different ...

for example: I have categories A, B, and C, I want to create a form to input and update categories A,B,C at once, but if the entered order_point values of any of the 3 categories are the same, then the form should not submit (for example A= 3, B= 2, c=2).

I created the form the could update multiple records values at once using f.number_field which is nested in fields_for, here's my code:

<section class="container page-container">
  <table class="table">
    <thead>
      <tr>
        <th>Name</th>
        <th>Arabic Name</th>
        <th>Order Strength</th>
        <th colspan="3"></th>
      </tr>
    </thead>

    <tbody>
      <%= form_tag admin_category_submit_order_categories_path, method: :post do %>
        <% @categories.each do |category| %>
          <tr>
            <td><%= category.name %></td>
            <td><%= category.ar_name %></td>
            <td>
              <%= fields_for "categories[]", category do |f|%>
                <%= f.number_field :order_point, value: category.order_point, in: [email protected]+1 %>
              <% end %>
            </td>
          </tr>
        <% end %>

        <div class="col-md-12">
          <%= submit_tag("Update", { class: "btn btn-primary pull-right"}) %>
        </div>
      <% end %>
    </tbody>
  </table>
</section>

and here's a screenshot:

knowing that order strength is the order_point attribute

any solutions?