Process of grade distribution decision

This is such a hard process because everyone has conflicting ideas as to what is important in determining a grade. With a group as large as ours, it's normal that people will have different ideas. It would be more strange if everyone in our group agreed 100% on how to break up the grades. We cannot design a process to bring us to a conclusion because throughout our lives we have been taught to place the emphasis of our grades on different things. Some people like taking tests and place a lot of importance on this aspect of the grading system, while other people are more abstract thinkers and would rather have the weight of their grade placed where they feel they exceed- in group discussion.
It is very frustrating to work in a group where one or two people refuse to compromise at all, no matter what compromise is made, and stick to their personal opinions without budge. In order to make a good decision all people must be willing to compromise.
In order to succeed in decision making there must be a democratic structure with guidelines and rules that have been predetermined. In a classroom setting it should be up to the discretion of the instructor to layout a method of grade distribution, or give choices and allow us to choose from there. In a group this large, filled with students who all want what they want (some of whom will not move an inch from their own standpoint) there needs to be some sort of preexisting format to guide us to a successful decision.