Multiple WordPress addresses (URLs) possible?

Hi, my second day with WordPress!

I’m self-hosting on a VPS that’s serving a few domains. The domains’ DNS all point to the same IP address, and the apache configuration routes the different domains to different WP installations in separate folders. This all works properly.

I would like to administer the WP installs over SSL, since logging in requires typing passwords, but since the server has only one IP address, the domains must all be served from the same virtual host. It would be nice to set the URLs up like this:

https://www.foo.com/wordpress ==
https://www.admindomain.com/foo/wordpress
https://www.bar.com/wordpress ==
https://www.admindomain.com/bar/wordpress

And so on.

I have made the necessary configurations on the Apache side for the admindomain.com URLs, however, WordPress isn’t happy with it, and always redirects the browser from the admindomain URL back to the original foo.com or bar.com URL.

Is there a configuration setting within WordPress to allow multiple (or arbitrary) URLs to the same install as there was with b2evolution? If not, is there a known way to perform this trick, perhaps with some mod_rewrite antics?

Thanks for any tips!

John