Correct! theres 2 teams, one team is the main team that handled Unleashed and Generations while the B-team handled Colors and Lost World. they switch off every other game.

~Unleashed - A-Team
~Colors - B-Team
~Generations - A-Team
~Lost World - B-Team

B-Team is usually known for handling the Nintendo versions of games, they were the team that was made for the Storybook games (Secret Rings and Black Knight) after the Sonic 2006 port failed to work on the Wii console.

Fun fact, The hackers at Sonic Retro discovered that the same engine that was used for the Storybook games was stripped and rebuilt into the Colors engine. the code markers match up with allot of Black Knight's code markers same with Secret Rings. Also Colors used allot of Generations made assets like enemies and level assets (springs and such) seeing as the file naming was the exact same in both games, its possible they borrowed these assets to save time while Generations was in development at the same time.