This paper deals with a forced vibration of strongly coupled subsystems. A theoretical and practical approach is proposed to obtain targets of the subsystem's vibration properties which fulfill the target of whole system. The approach is an application of transfer function synthesis method and provides a procedure to analyze the compliance of subsystems at connecting points for setting the natural frequency and reducing the internal forces. A new concept of kernel dynamic stiffness and kernel vector is introduced to understand vibration transmission in the analysis of the compliance at connecting points. This approach is applied to vehicle noise issue induced by road roughness (road noise) in the frequency range of 80 Hz and 150 Hz on macpherson strut type suspension. The results show effectiveness of this approach and present guideline of the suspension design for road noise.