Multiple domans?

[dmgd]

I host a few sites with one account using plesk control panel.  The file directory is setup as:
/home/myaccount/site1.com/  -> www.site1.com
/home/myaccount/site2.com/  -> www.site2.com
/home/myaccount/site3.com/  -> www.site3.com
. . .

Is it possible to have core CMSMS files in a dir on the same level as the domains like,
/home/myaccount/cmsinstall -> contain all core files and directories i.e. /admin /modules, /plugins, /lib etc.

And use the single install for the all the domains?  Each domain would have
/uploads -> all user uload files,
/tmp -> site cache files
index.php -> entery page
config.php
.htaccess
admin/index.php -> admin page

Mark