Okey I Found A Way To Do This :)
Content.makeFrontInterface(600, 100);
const var SimpleGain = Synth.getEffect("Simple Gain");
const var Button1 = Content.getComponent("Button1");
const var Button2 = Content.getComponent("Button2");
const var Button3 = Content.getComponent("Button3");
reg BTNONE;
inline function onButton1Control(component, value)
{
	if (value)
    {
       BTNONE= -10; 
    }
    else
    {
       BTNONE= 0; 
    }
    
    Button2.changed();   
    Button3.changed();
};
Content.getComponent("Button1").setControlCallback(onButton1Control);
inline function onButton2Control(component, value)
{
	SimpleGain.setAttribute(0, BTNONE -5);  
};
Content.getComponent("Button2").setControlCallback(onButton2Control);
inline function onButton3Control(component, value)
{
	SimpleGain.setAttribute(0, BTNONE -10);  
};
Content.getComponent("Button3").setControlCallback(onButton3Control);