...
Note. Initially, the fields are populated with the default GL accounts for all employees. To access these default accounts, click the Employee GL Accounts link on the top of the Employees list—this opens the Employee GL Accounts form. The default accounts are listed in the first table row for which in the Employee column there is no name.
If you need to use specific GL accounts for employees of this group, edit the accounts listed in this dialog box.
...
The assigned accounts will be used as default accounts in documents for all employees of this group unless for some of these employees another set of default accounts has been assigned.