  We give a construction of a wide class of modular symbols attached to
reductive groups. As an application we construct a p-adic distribution
interpolating the special values of the twisted Rankin-Selberg L-function
attached to cuspidal automorphic representations of GL(n) and GL(n-1) over
number fields. If the representations are ordinary at p, our distribution is
bounded and yields analyticity of the associated p-adic L-function.
