Use same plugin across mutiple WP blogs that are on subdomains?

Hey. I have mutliple WP installations which reside in internal folders under the public_html, and each one of them is accessible through a different subdomain (personal.al-rasid.com. cinema.al-rasid.com. etc).

There are many plugins that I need on all of them. The traditional way is to install the same plugin on every installation. But this is wasting too much space and puts my file count at risk of reaching the most file count allowed by my shared hosting, especially by plugins which have many files.

So is there no way to install the plugin on one installation only and use it on all installations which are in the same host, given that they require the same configuration?

I know there is WP-Multi, but I am not interested in this solution currently.

Thanx