Open more than one faceplate in operaotr station

Hello

Our DCS control system is ABB System800xA V5.1 FP4.We want add a facility to the system that operators be able to open more than one faceplate simultanetly in HMI.In ABB manual is written,that the aspect (View class) must be configured,but I don't know for which object this must be done.I would kindly requseted to help me.

Thanks a lot.