controller synthesis for disturbance rejection

Hello all,

I need to design a stabilizing controller K (for known s-plane transfer function models G and H, both containing delay terms;pade approximated) such that the bode magnitude of the closed-loop transfer function G/(1+K*H) is minimized in a certain frequency range of interest. Basically, the idea is to attenuate the magnitude of the open loop transfer function G in that frequency range.

I looked up Hinfinity methods but couldn't quite get them to work for this problem.

Any suggestions on how to achieve this using MATLAB would be greatly appreciated. Thanks a lot for your attention!