There are a couple of ways you can do this. If you just want to differentiate the sales you could as @Accountant suggest create 3 separate nominal accounts for each of the pubs. You could also differentiate by using 3 clients (e.g. Pub 1, Pub 2, Pub3) or you could use project tags, although this method will probably be quite fiddly as you’d need to keep manually applying the tags once the invoices were created.