<VirtualHost *:80>
  ServerName abc.com
  ServerAlias abc.com www.abc.com
  RewriteEngine on
  RewriteCond %{HTTPS} !=on
  RewriteRule ^/?(.*) https://%{SERVER_NAME}/ [NC,R,L]
</VirtualHost>

RewriteCond %{HTTP_HOST} ^(www.)?abc.com$ [NC]
RewriteCond %{HTTPS} off
RewriteRule ^/?(.*)$ https://%{HTTP_HOST}/$1 [NE,R,L]

RewriteCond %{HTTP_HOST} ^(www.)?xyz.com$ [NC]
RewriteCond %{HTTPS} on
RewriteRule ^/?(.*)$ http://%{HTTP_HOST}/$1 [NE,R,L]