Is it Possible to remove the download photo option for registered user

Hi...

I love Gallery 3... but one thing I havent been able to work out is as follows (which is probably dead simple.. sorry not that techy)...

I have worked out how to allow users to download full size images and albums in a restricted album (group) that requires username and password... But I cant work out how to remove the download option for users viewing a restricted album that requires a username and password to view... pretty sure I am missing something but...Is this possible..??

My goal is to allow some users to have full download priv for certain albums and other users / albums to need to go through eCommerce shopping cart.

Hope this makes sense

tim