Look at “posts/pages edit access restrictions” add-on. It has Allow – ‘Own data only’ option. It works for any custom post type too. So product owners will see and can edit at back-end just there own products and related orders only.
This restriction is possible to set as per user via user profile, as per role via role editor.
May be it will be suitable to resolve your task, but may be it’s better to look for a special vendors plugin too.
