How to subscribe the button event in someother event

Hi,

There are 2 buttons on one of the assignement block on overview page, now i have created 3rd button on overview page toolbar...now i want to subscribe those two buttons events from this button on overview page toolbar

each button having different functionality,  button1 will do export the records into excel, 2nd button will change the look of the view

pls help me on this.

Regards,

RV