Specific Posting Groups (Customer, Vendor, Inventory, Bank & Fixed Assets), is linked a GL Account on the Balance Sheet.

Each Specific Groups eg Customer, is linked to GL Account which is driving Accounts Receivable, and Intercompanies.

Your AR aging (Customer Ledger Entries) can be filtered by Customer Posting Group, which is supporting the AR GL Account (GL Entries). In fact your GL balance sheet account is supported by the results in your subledger (customer ledger entries).

It is recommended to set the GL account linked to the AR, as "Direct Posting" = No.

For audit requirements (and data governance, reporting), it means a big recommendation.

I remarked with different customers, as it is so simple to change these specific posting groups, that they do not understand the effect of changing the posting groups.

It should be an option in the setup of your system.