two-way street
mutually
bilateral
go halves
two-way
liaise
corespective
equalism
intercession
impartial
intermediate
intercede
polder model
mediate
arbitrate
equally
corresponsive
shareout
panarchy
cooperative
constructive force
six of one, half a dozen of the other
cartel
equifacial
dialogue
synallagmatic
win-win
dialog
deal
tripartisanship
backscratch
level set
it takes two to tango
arm's length principle
Switzerland
equivalence
similiter
fairly
cat and mouse
equidistribute
concurrent
omniparity
takeover
mediation
bilaterally
made for each other
good faith
covenant
swop
trade
evenhandedly
swap
barter
bipartisanship
cross-party
fair
seat at the table
multiparty
law of action and reaction
interresponsibility
equivalent
Newton's third law
will contract
agreeingly
requirements contract
Newton's third law of motion
reciprocal
third law of motion
without fear or favour
both-sides
peel
interplaying
uniparty
inter partes
isocracy
equality
concert
entente cordiale
conditional agreement
cooperability
correlate
sweetheart deal
modus vivendi
go for
match
mutual
trench mentality
even-stevens
eunomy
common
high road
according