Controlling a Generator in Manual and Auto Modes

I have four generators in a power system,out of that one generator has superior frequency response than others, i.e, it has high gain 1/R. Now while picking up a certain load in some bus, that given generator takes a large share of the load and overloads the line connecting it to the load. In order to avoid this overload, i want to cut off the governor signal of this particular generator and allow the load to be picked up by the auto governor response of three remaining generators and thus to regulate the frequency. Now is this possible? If its possible, i want to know how can the generator be shifted to manual control so that auto governor response (depending on frequency deviation) is disabled temporarily for some period.?

Now if the given line flow decrease due to say some parallel line switching, reducing line overload possibility, then again i want to set this particular generator in auto governor response mode like others. now Can i change from manual to auto mode this frequently in the operation?This is for my masters thesis project in college where i perform restoration of a system.