I'm trying to consider my structure carefully and I'm wondering what is best practice for a configuration where one group title that could reside in multiple parent groups. Here is an example of a typical use case that has this consideration.
Parent Group #1: Dogs
Subgroups Tier 1: poodles, sheepdog, all breeds:
Subgroups Tier 2: training, diet, health
Parent Group #2 Cats
Subgroups Tier 1 : domestic short hair, siamese, all breeds.
Subgroups Tier 2: diet, health, litter boxes
Given that the "all breeds, training, diet, health" appear for both parent groups within different subgroup tiers, what is the best way to structure this set up?
Do I create just one node for all groups and distinguish the reoccurances with unique titles (e.g. dogs-health; cats-health)?
Is there a better approach?
Thank you kindly for your consideration.

Comments
node reference worked for me
I've done this using node reference before. Steps are:
1. use CCK to put a node reference field on your group - call it "parent group"
2. set up that field to point to other group nodes
3. an autocorrect text field usually works well for me, because as groups are added the options list can get too long
After that's set up there are a number of ways that you can display the subgroups, especially with views. This works for simple applications - the only gotcha is that each group will stand on its own. So, just because you're a member of "siamese" doesn't mean you'll receive things for "cats" and so forth. For more complex uses, might want to check out a module - I'm sure there must be one called "og_subgroups" or something.
I'm Using OG Subgroups
I am using the OG Subgroups module. As we discussed on IRC, naming the group with a qualifier "cats-all breeds" would work, but I can't help but wonder if there is a more elegant approach?
*_*
I am able to use the group and creating the hierarchy. But when a user subscribes to (automatically, usiung the zip code when registering, in my case) a subgroup, s/he doesn't subscribe to all the parents of that subgroup.
Is there any work around this?
Regards.
BeautifulMind