Grad student protecing ideas in research paper for futher development

I am working on a graduate school research paper in finance/accounting. My adviser is really excited about my paper and this professor is a prolific publisher. The paper has progressed enough to hand in for the course. I want to develop this paper further after the course is over. However, after meeting with my adviser, (her student assistance's desk is in the professor's office) three other grad students are doing their papers on the same subject. How can I turn in the paper but protect the work so I can further develop it on my own time? I put a qualifier (not to use without my permission) on the paper but the professor wants it removed. I explained that I wanted to further develop it but he said it is for others to use.