Currently, when dividing up players into groups, they are sorted by rating and then allocated as follows (using a 16-player tournament with groups of four to illustrate):
Group 1
Group 2
Group 3
Group 4
Player 1Player 5Player 9Player 13
Player 2Player 6Player 10Player 14
Player 3Player 7Player 11Player 15
Player 4Player 8Player 12Player 16
This has the rather obvious effect of making Group 1 considerably stronger than Group 4. The difference could even encourage small-scale sandbagging, as Player 5 might try to drop a couple games to chop his rating down so he becomes Player 8.
A better method that would result in all groups being about the same average strength would be to use a snaking system:
Group 1
Group 2
Group 3
Group 4
Player 1Player 8Player 9Player 16
Player 2Player 7Player 10Player 15
Player 3Player 6Player 11Player 14
Player 4Player 5Player 12Player 13
This system will result in all groups being roughly equivalent. It also discourages sandbagging, as, if anything, you'll tend to get a stronger group. For example, if Player 5 drops down to become Player 8, the bottom two members of the group will average about the same, but his top opponent will now be Player 1 instead of Player 4.