RewriteEngine on

RewriteCond %{QUERY_STRING} page=members.*
RewriteRule ^ /members

<LocationMatch ".*/members">
SSLVerifyClient optional
SSLVerifyDepth 1
</LocationMatch>

RewriteCond %{SSL:SSL_CLIENT_S_DN} ^$
RewriteRule ^/index.php?page=members /index.php?page=members [S=1]
RewriteRule ^/index.php?page=members /index.php?page=members2