I have various assignment groups with a weight assigned for each of these groups. The total weight of the group sums to 100%. Now under each group I have multiple assignments. Lets say I have a group named 'Quizzes' whose weight is 15% of the total grade, under this I have lets say three quizzes Quiz1, Quiz2 and Quiz3. How can I give a weight of 20% for Quiz1, and 40% each for Quiz2 & Quiz3?