A formalism for measuring time-dependent CP violation in B_q -> J/\psi h+ h-
decays with J/\psi-> mu+ mu- is developed for the general case where there can
be many h+ h- final states of different angular momentum present. Here h refers
to any spinless meson. The decay amplitude is derived using similar
considerations as those in a Daltiz like analysis of three-body spinless mesons
taking into account the fact that the J/\psi is spin-1, and the various
interferences allowed between different final states. Implementation of this
procedure can, in principle, lead to the use of a larger number of final states
for CP violation studies.Comment: To be published in Physics Lett. B, 11 pages 1 figure, version 2,
fixed error in middle term of Eq. (23