Saya rasa diserap saja. Jabatan ini jamak dikenal di bidang periklanan; melihat fungsinya, sepertinya untuk sekelompok akun [besar], itu mungkin alasan disebut dengan group account.

√ Pada surjaya, seorang direktur akun grup bisa membawahkan beberapa account director.

SURJAYA ★★★★★
http://www.communicationscouncil.org.au/public/content/ViewC...
As an Account Director, you will also need to learn presentation skills, as you will be regularly called upon to present creative work and marketing strategies to groups of clients. In larger agencies, you'll report to the Group Account Director or who is responsible for several accounts....