Two WordPress installations, in different subdirectories on same root domain

Hi, I need to have two wordpress installations on the same root domain, each in a different subdirectory and need help with htaccess rewrite

Example:

www.mydomain.com
root folder
Install1
Install2

The root folder does not contain a WordPress installation or anything else executable.

Requests to the root domain should all go to Install1 directory unless the URL specifically requests www.mydomain.com/Install2, at which point the second full installation is utilized including wp-admin

The htaccess file should also redirect requests to the www form of the domain and the https protocol, along with index.php if no file or folder is specifically requested.

I have found information on redirecting an installation to a subdirectory, but not the specific case of two subdirectory installations, and combined with www and https directives.

Any help is appreciated,
Bill