  Coordination is a challenging everyday task; just think of the last time you
organized a party or a meeting involving several people. As a growing part of
our social and professional life goes online, an opportunity for an improved
coordination process arises. Recently, Gupta et al. proposed entangled queries
as a declarative abstraction for data-driven coordination, where the difficulty
of the coordination task is shifted from the user to the database.
Unfortunately, evaluating entangled queries is very hard, and thus previous
work considered only a restricted class of queries that satisfy safety (the
coordination partners are fixed) and uniqueness (all queries need to be
satisfied). In this paper we significantly extend the class of feasible
entangled queries beyond uniqueness and safety. First, we show that we can
simply drop uniqueness and still efficiently evaluate a set of safe entangled
queries. Second, we show that as long as all users coordinate on the same set
of attributes, we can give an efficient algorithm for coordination even if the
set of queries does not satisfy safety. In an experimental evaluation we show
that our algorithms are feasible for a wide spectrum of coordination scenarios.
