KCL at Vout Node :
( Vout/(Rf1+Rf2) ) + ( Vout / ZL(s) ) = ( (Vin-Vout)/rds ) - gm*( Vout*( Rf2/(Rf1+Rf2) )*( Aeo/(1+s/wc) ) -Vin )
I think the last term is what you can't figure out.
Since it's small signal transfer function, do not consider DC part.