I want to ask if its possible to have a 15% contractualization type of operation for a company with almost 85% manpower ratio was regularized and Can I make it 85% contractual vs. 15% regularized what agreement should I implement?

I want to ask if its possible to have a 15% contractualization type of operation for a company with almost 85% manpower ratio was regularized and Can I make it 85% contractual vs. 15% regularized what agreement should I implement?