Page level permission to a user group

It would be great if there was a simple way to give a view permission (on a page) to a specific user group - for example just through checking a box on a specific page.

In our case, we are thinking of integrating our partners (which would then be all in one user group) into our wiki by granting them view permissions to some specific pages. Currently, our partners don't have any access rights at all.

I don't know of a plugin that is able to do this.