Like which shopkeepers have a particular product, we created a custom doctype and added the item in it and created a custom table in which we have to add the mail of every shopkeeper who has that item and send a message to all of them at once asking if you have this product or not and if yes, then at what price and we also want to mail more than 100 people at once
that for, you have create a workflow and some customization needed for email for this (send a message to all of them at once asking if you have this product or not and if yes)