UnitedHealth Group is bidding for the ambulatory unit put up for sale by Envision Healthcare Corp, Bloomberg is reporting. Separate groups of PE firms, including a consortium comprised of Hellman & Friedman, Onex CorpĀ and Clayton Dubilier & Rice, as well as one group led by Carlyle Group LP, are still interested in buying the whole company but would be open to acquiring parts, the story said.