My individual ideas will be lost
Fact or Fiction? Both
In any group, no one's ideas count more than another's; as a result, you will not always get a given idea into a paper exactly as you originally thought it. However, getting your ideas challenged and changed is the very reason to do a group project. The key is to avoid losing your ideas entirely (i.e. being silenced in a group) without trying to control the group and silencing others.
It's okay to argue. Only through arguing with other members can you test the strength of not only others' ideas but also your own. Just be careful to keep the disagreement on the issue, not on personalities.
Encourage a Collaborative Attitude
No paper, even if you write it alone, is solely a reflection of your own ideas; the paper includes ideas you've gotten from class, from reading, from research. Think of your group members, and encourage them to think of you, as yet another source of knowledge.
Be Ready to Compromise
Look for ways in which differing ideas might be used to come up with a "new" idea that includes parts of both. It's okay to "stick to your guns," but remember everyone gives up a little in a group interaction. You must determine when you're willing to bend and when you're not.
Consider Including the Disagreement in the Paper
Depending on the type of paper you're writing, it's frequently okay to include more than one "right" answer by showing both are supportable with available evidence. In fact, papers which present disagreement without resolutions can sometimes be better than those that argue for only one solution or point of view.