back to back (?.)
- as one
- as one man
- at opposite extremes
- behind
- behind the scenes
- coactively
- coefficiently
- collectively
- combinedly
- communally
- concertedly
- concordantly
- concurrently
- conjointly
- contrariwise
- contrary
- cooperatingly
- cooperatively
- counter
- eyeball to eyeball
- face to face
- hand in glove
- hand in hand
- harmoniously
- in back of
- in chorus
- in concert with
- in the background
- in the rear
- in unison
- jointly
- just opposite
- nose to nose
- opposite
- poles apart
- shoulder to shoulder
- tandem
- together
- unanimously
- vis-a-vis
- with one voice