By default the blizzard raid frames will grow from left to right, up to down. In my case, since I want to have the frames on the right side of the screen I would want the frames to grow from right to left, up to down. Can you add that option ?
Note that there are 2 ways to do this:

1. by maintaining the first group of players always on the far right on a static position and grow other groups left from there (so basically you are adding groups to the left of the first group instead of right).
2. dynamically move the first group of players to the left when new players fill up more groups to the right (so basically you are adding groups to the right of the first group just like normal but you are also moving the entire raid frames to the left to make room for new groups in the right). Personally I would prefer having it this way.

For reference another popular addon called Grid2 allows us to do this with 'anchor' options, so I guess it's possible.