This command would result in an error because a disk group can have only one failover group.
This command would result in an error because the /devices/A1 disk is a member of another disk group tdgroup1.
A new disk group called tdgroupA will be added with two failover groups and the /devices/A1 disk will get reattached to the new disk group without being detached from the existing one.
A new disk group called tdgroupA will be added with two failover groups and the /devices/A1 disk will be ignored for the new disk group because it is a member of an existing disk group tdgroup1.
A new disk group called tdgroupA will be added with two failover groups and the /devices/A1 disk gets detached from the existing disk group tdgroup1 and attached to the new disk group tdgroupA