Hello Patrick
The multicast addresses that you can use are in the range of 224.0.0.0 to 239.255.255.255, but there are some reserved addresses within that range. The IP addresses you are using are all within the free for use ranges, except for 224.0.1.60 which is a well known multicast address registered as hp-device-disc as seen from the IANA address. Without researching it further, it is likely used by a service on an HP network device.
Now having said that, how do you know what groups to create? It depends on what you want to achieve. Remember that the groups are actually created by the hosts trying to join a multicast group. It is the ip igmp join-group command (in the case of a Cisco device) that causes a host to begin sending join requests, which eventually adds the multicast group to the routing table of the routers. (In the case of a computer, the OS is responsible for sending out these join requests based on some application that is managing these communications.)
So what groups will be created simply depends on the hosts (and the multicast sources) and the applications that they are running.
I hope this has been helpful!
Laz