I want to know if it is possible to do HSRP with 3 or more routers.
Yes, it is perfectly possible. From Cisco's HSRP documentation:
It works really the same as two, except instead of 1 in two holding the virtual ip, 1 in 3 will hold the virtual IP. By setting priorities, you can set preferences as to which will have it when all three are up, or if only two are up.