Improve code comment about group mapping
Created by: kfogel
(See https://chat.opentechstrategies.com/#narrow/stream/45-Lever-for.20Change/topic/API/near/97885 for context.)
Created by: kfogel
(See https://chat.opentechstrategies.com/#narrow/stream/45-Lever-for.20Change/topic/API/near/97885 for context.)