Why are instances of duplicated groups linked I'm a bit of a newb, so please bear with me.
I have a number of objects (chairs) that are parented to another object (table). I have created a group of these objects and have many instances of this group. I was hoping to be able to duplicate the original group of table and chairs as I want to make slight adjustments to the duplicated group and in turn make instances of this new group.

However, once the group is duplicated there appears to be a link between the first instance of the first group and the first instance of the second group, so if I delete an instance from the second group, then it will also be deleted from the first group. Is there a way to duplicate the first group so I can modify the elements of the second group without it effecting the first group.
Thanks in advance.
Russ
An object can be a member of more than one group, they are more like tags or lists of objects than "groups" in the more traditional sense. So if I'm understanding your post correctly, you can make a group for the first table/chair set, then another one for the second set. Any objects you want in both sets, just add them to both groups.