I think you're missing something rather big here though. RP or not, people Intentionally will have some alts in one group and some in another. Especially those from the OG. What you're suggesting (if it were even Possible, which it's already been suggested is Not) would result in a mess where Every alt you make will go into that SG.
Now, think about this a minute. Just think about how big those ranks will get in a hurry. IDK about you, but I've already got about 4-5 dozen alts (most are OG remakes). Now imagine you get say 5 of us like that in a group and then somebody wants to go change a rank. Something rather simple and normally quick-ish depending on sorting and activity. Even if you expanded the group window from top-bottom of a screen, it would take maybe half a dozen pages to Read just to find that alt.
Oh and don't forget about the bases. Your first problem will be sharing storage. We already know the storage limit is EASY to hit with a Single hoarder in the base, but imagine trying to share with hundreds of alts vs a couple hundred. Ok, you can set rules on that and hope they're followed.
What about when you get a couple hundred people hanging out in the base and a few of them happen to be multi-boxing...do you like HARD crashes, because that's how you get server/instance killing crashes.
The point is, until the database issue gets a work around (I'm assuming that means when they get time to dump the spaghetti and build from scratch), we're likely going to have to just deal with this as is and how we've managed before. Creatively, with coalitions, and the understanding that while we're lucky the game is back, we're even luckier it happens to work due to some very creative fixing back in OG.