Time capturing Business scenario

Hello Friends,

I have a requirement and i need your suggestions to achieve this in system.

My requirement is " PS project with activities is created and person assignment is maintained and the person assigned will use the CATS to book the time, but the real issue is with the contractors, the contractor details is not maintained in the system but we have to capture there time, How we can achieve this, the project manager has to book the time on behalf of the contractors, on purchase order or service request without maintaing the contractor details in the system.

Any suggestions will be helpful.

Thanks,

Lohith