Original: The Seiko Group consists of Seiko Holdings Corporation (Seiko), Seiko Instruments Inc. (SII), and Seiko Epson Corporation (Epson).
Simplified: Seiko is one of the three main companies of the "Seiko Group" which are the Seiko Holdings Corporation (Seiko), Seiko Instruments Inc. (SII) and the Seiko Epson Corporation (Epson).