What do you mean, sorting by time ? (by hours of the day ?)
The issue here is not setting a group as a permission, it's detecting that the user is in this group, and that takes A LOT OF TIME as the groups API is really slow.
It's an interesting idea, can you give us more details on how you would re-use it ?
Also do you know you can already make direct link to pre-filtered Awesome Table views ? Does it do what you want ?
(here the link to the article explaining it : http://goo.gl/dAPgtB)