How do i auto-wrap a link with a certain class with a shortcode?

I use auto blog to curate content to my site. in all of my auto created posts i have outbound links with certain class declared on them.

I want to auto-wrap those like with my shortcode.

how can it be done?

for example:

i have this link on posts:

Ben

and i want it to be this automatically:

[ben]Ben[/ben]

thanks!