Yes that solved the issue with user site, and now I can add the /index to base_url[index] in config as
base_url[index] = http://aro.koyauniversity.org/index
base_url[aro] = http://aro.koyauniversity.org
restful_urls = on
but still I have to have redirection to my htaccess to make the short URL work
RewriteEngine On
RewriteCond %{HTTP_HOST} ^aro.koyauniversity.org$
RewriteRule ^$ http://aro.koyauniversity.org/index [L,R=301]
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-d
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^/index/(.*)$ /index.php/index/$1 [L]
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-d
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.*)$ /index.php/aro/$1 [L]
</IfModule>
BTW, in the direction you have provided on MAY 15 above on the last line one have to have it should be a / after SHORTNAME to read as below, without it it does not work
RewriteRule ^(.*)$ /index.php/SHORTNAME/$1 [L]