changing url via shortcode

I searched the FAQ and the support forum, but could’t find anything about the following:
I want to add via shortcode all configured buttons inside a page, but the url, the buttons should share, has to be another one.

For example:
[really_simple_share url=”yxz”]

thanks,
Daniel

http://ww.wp.xz.cn/extend/plugins/really-simple-facebook-twitter-share-buttons/