How do I use different hourly rates for different people and their tasks when invoicing from Zoho Projects?

How do I use different hourly rates for different people and their tasks when invoicing from Zoho Projects?

When I create an invoice out of Zoho Projects (Timesheet tab), I'm asked for just one hourly rate.  I need to use a different hourly rate for different people, even if they are putting time in on the same task.

I know I can break out lines in the invoice separately to accomplish this, but that is, obviously, manual and risky.

How do I do this automatically?

Can I enter a billable rate for an individual somewhere?

On the invoice, can I specify which person the hours are associated to, then change the billing amount for each of those line items?

Thank you,
Kenny