You can add multiple contacts for each supplier and set one contact as the primary.
When you navigate to the Contacts tab of your Suppliers, you may see that one of the contacts is labelled as "Default Primary". This is the primary contact set by your Supplier - it could be your sales rep, the accounts team, or it could point to a generic mailbox like "sales@....com" or "info@....com". This contact person will appear as the primary contact when you click on "Supplier Info" of an order.
You may have a specific individual whom you liaise directly with, perhaps your designated sales rep or account manager. You can indicate that person to be your primary contact. This way, you can easily access the contact number if you need to contact them.
You can also make changes to the types of notifications sent to your Supplier on the Order Notification tab. Maybe the Sales Rep doesn't need get cc'd on all of the orders, then you can turn off all the notifications.