  We present branching fraction measurements of twelve B meson decays of the
form B --> D^(*)D_s(J)^(*). The results are based on Y(4S) decays in BBbar
pairs. One of the B mesons is fully reconstructed and the other decays to two
charm mesons, of which one is reconstructed, and the mass and momentum of the
other is inferred by kinematics. Combining these results with previous
exclusive branching fraction measurements, we determine BR(D_s^- --> phi pi^-)
= (4.62 +/- 0.36_stat. +/- 0.51_syst.)%, BR(D_sJ(2460)^- --> D_s^*- pi^0) = (56
+/- 13_stat. +/- 9_syst.)% and BR(D-sJ(2460)^- --> D_s^- gamma) = (16 +/-
4_stat. +/- 3_syst.)%.
