Use one form for all the different supplier pages. Don’t make multiple forms.
If you can store the supplier email in the post meta for the post (this is key) you can also do this:
Add an email field to the form. Give it a default value of {custom_field:supplier_email} (assuming you stored their email address in a custom field with the meta key ‘supplier_email’). You can make this field hidden if you want to, so it’s not shown on the front end of the form.
Then, you can select this email field in your “Send To” for the notification. Select the “Select a field” radio button, then select your “supplier email” field in the dropdown. That will populate the notification with the email address that was pulled from the post custom field.
Either way should work. If you need any other ideas, please let us know.