My end client has different projects for the worker to work on and it needs to be broken down on their timesheet. Can this be done?

Different projects, and project codes, POs can be managed within the timesheet system in various ways

Yes, separate line items can be set up to reflect different projects and would be labelled as such. The responsibility of selecting the correct project to assign time to would be up to the contractor and timesheet approver at the end client. There would be one invoice issued noting each project that has time assigned at the end of each invoicing cycle.