As you will notive from googling the term, 'supply group' often refers to power supply companies, organisations etc.. The term can also mean the groupwise supply of electrical power to devices, installations, circuits etc.

http://www.freepatentsonline.com/EP0524113.html
4. Connection element according to Claim 2, characterised in that the moulded portion of the female portion is constituted by two units: a first unit (6), moulded over the electrical connection (9) and elongated and extended by the electrical *** supply group ***, a second unit, making up the pincer (3) proper, at the level of one of the ends (5) of which the first unit (6) is inserted, the said pincer comprising at the level of its medial zone, a slot (10) intended to allow access to the male blade terminal (2) so that the latter can lodge in the female connection (9), the said pincer (3) being fixed by its other end (4) on the surface (8).

http://www.alibaba.com/product-gs/219452018/Electric_Dust_Co...
Electric dust collector is a dusk collection device for realizing the separation of particles and air stream by electrostatic force. The body of electric dust collector is a high-voltage electric field provided by high-voltage electric power *** supply group ***, which control low-voltage control cabinet with high-voltage pulsating direct current and low-voltage control cabinet,and the dust trapped sent to storage hopper by dust unloading and carrying device.

http://www.tpub.com/content/MIL-SPEC/MIL-A/MIL-A-55147B/MIL-...