Thanks for being our VIP member. The solution for your case is to get proxy servers via different download links. The KEY will be the same for all links but filter options may be changed. For example:

Transparent:
http://freeproxylist.org/en/downloader.php?key=jQbQYleis59b48nyV4oN0fwUCzaVqWIl&filter=any|any|1|any|any|any|0|0|15.0000|0|360

Anonymous:
http://freeproxylist.org/en/downloader.php?key=jQbQYleis59b48nyV4oN0fwUCzaVqWIl&filter=any|any|2|any|any|any|0|0|15.0000|0|360

Elite:
http://freeproxylist.org/en/downloader.php?key=jQbQYleis59b48nyV4oN0fwUCzaVqWIl&filter=any|any|3|any|any|any|0|0|15.0000|0|360

You may play with other options too.