Using views to display posts in all groups that any user belongs to

Hi all, I'm having a bit of a quandry because I think I'm trying to do something that might not possible using the Views module: I'm trying to display recent posts from all the Organic Groups that a user belongs to. For example, say I have a user whose has a drupal username of "ben" and belongs to three groups. There is a page for each user on the site, in the format "users/[username]", so in this case we have the page "users/ben". On this page I'd like to list recent posts made in all three groups that ben belongs to. Note, these posts could potentially be written by any user who belongs to these groups, not necessarily just by ben.

There is a built-in view in the Organic Groups module, "og_mytracker", that displays all of the logged-in user's groups activity. This is close to what I'd like, but slightly different. I'm looking for a the groups activity for any given user.

I believe that I'd have to pass the username as an argument to the view. But as far as I can tell, I can only tell the view to limit the output to posts by this username. I'm unable to discover if I can tell the view to get posts from all users in this persons groups. Does anyone know if this is possible?

Thanks very much in advance for any assistance or advice.