Single merchant has multiple products, We need separate chat option for each product using XMPP ejabberd connection

I'm going to implement chat option in my project using XMPP ejabberd. In my project, we have a merchant to create multiple products (like selling goods). We need to implement each product have a separate chat option. For example, Merchant John has two product like Mobile and Car. Now User Mark Interested John Mobile he chooses mobile and chats. Like Peter Interested John Car he chooses a car and chats. Please give me a perfect solution for this concept.

Note: We already implemented one to one chat.