Before anything let me just say that this is not how NS works. The whole purpose of having one COA is to make NS system driven, and you are trying to break it. You would be better off having it all in one sub, having classes and locations with the associated P&Ls and BSs. NS is designed to simplify your accounting, not complicate it. Just an opinion. COA has a bit different meaning in NS, not like in any other system where COA is everything. Instead of summary accounts, for example, I teach my clients to use segments (class, department, custom segment, etc.) and custom P&Ls and BSs. You may want to rethink your approach because implementing it will be difficult and maintaining it even more so as you inevitably run with Accounting Context. But technically - yes, since there are no statutory restrictions per se you can create multiple COAs using accounting context; you will have to always maintain one-to-one relations between parent COA accounts and the remaining COAs accounts.