From what I understand, you’re looking to use the same nominal codes for 3 different outlets but on one set of accounts.
If that is the case, you’re not able to separate entries within the Chart of Accounts (COA) to different outlets etc. However, QuickFile introduced the project tags a few years ago which may help.
Project tags can be applied to whole invoices, estimates and purchases, and general a P&L report based on the tagged data.
I hope that helps.