Transformers Combiners are groups of 2-6 bots who combine into a more powerful super-bot. In later continuities, the combined super-bot is controlled by one specific member of the group. For example, Ruination from Robots in Disguise is controlled by Mega-Octane; In Transformers: Energon, the combined mode is controlled by whoever forms the top/torso.
I have been unable to find any such rule - if there even is one - for Generation 1 Transformers. Does any one Transformer/member of the group control the combined mode? Is the combined mode its own separate consciousness? Bruticus (the combined form of the the Combaticons) refers to himself in the third person. Even the Constructicons speak of Devastator almost as a separate entity.
SCRAPPER: The Constructicons form Devastator, the most powerful robot. We should rule.