is important?

A label associated with a group of related input elements also serves as a common label for individual inputs in the group. 
Assistive technologies (AT) can indicate the start and end of the group and the group’s label as the user navigates into and out of the group.
AT needs to be able to present the group label with each input control to remind users with which group they are part.
When there are multiple groups with the same input elements then the label of the group needs to be unique s