Using Authcache with Organic Groups?

Thanks for this great module! I'm actually using it on my social networking site (yes, I know you're not supposed to) but the exclude/include and rules settings are great! I simply exclude the personal content pages, ajaxify a few regions, and I'm all set! The rest of the site can be cached for logged in users.

Except for one problem...organic groups...I would LOVE to be able to cache OG content.

Here's the problem...

Let's say I have 2 groups:

Group A - 10 people
Group B - 10 people

These 20 people are all in the same role.

If 1 person accesses a node from Group A, that page will be cached. Normally, if a person from Group B tries to access that same page from Group A, he will get an access denied because he's NOT A MEMBER. However, since the 20 people from Group A and Group B are all in the same role, they can freely look at each other's pages.

Now one simple solution to this is to simply NOT CACHE the og home page (/og) or the front pages of the groups. This way, members won't have the chance to click on any group content.

But this makes me nervous...members could still access other group's content if they got hold of the URL...if they guessed...or if someone from another group gave it to them.

Does anyone have a workaround for this? Thanks in advance!