Exclude shopper group for specific product

[Khaostar]

Hi everyone,

Easy question today, but I can't find an easy solution.
I have thousand ou products and multiple shopper groups. What I actually want to do is to exclude some products for a specific shopper group. In other words, I want some products to be unavailable for a shopper group.

I know that I can simply add all shopper groups in all products and exclude the group I don't want for the concerned products, but that would be a pain because of the large number of products and groups that I have. So I would like to have an "exclude shopper group" instead.

Does anyone know a plugin or something that does that? 

Joomla 2.5.20
Virtuemart 2.6.6

Thanks!