We consider coherent transport in an arbitrary molecular complex functioning as N-terminal conductor. The matrices that enter Dattas trace formula for the transmission function T(E) are represented in terms of free-molecule Greens function matrix elements referring exclusively to molecular atoms perturbed by the lead-molecule interaction. Explicit expressions of transmission function are obtained for a commonly used model of multiterminal molecular devices, where the molecule is coupled with each lead via a single bond. In the particular cases of connection of molecular wires via a single atom and a benzene ring, this gives the analytical expressions of T(E). Physical implications of the derived formulas are briefly discussed.