Is there a way of using a separate "Accounts Payable" account for a specific supplier ? If so how to allocate the new A/P account only for that supplier's bills ?

Hi, @ariyasinghe-esof. I can see that it's a duplicate post. 

My colleague, MAJ already responded to your query. You can reply to her through this link so we'll be able to assist you further. https://quickbooks.intuit.com/learn-support/global/manage-suppliers-and-expenses/re-is-there-a-way-of-using-a-separate-accounts-payable-account/01/1419211/highlight/true#M4116

The QuickBooks Community team is always here to help if you have any other concerns or follow-up questions. Have a good day!