Make cost centre transactional?

Hi All,

I have a requirement in payroll reporting to make the cost centre of an employee 'as was'.

e.g

Jan 07 Emp1 cost ctr1 £1000

Feb 07 Emp1 cost ctr1 £1000

Mar 07 Emp1 cost ctr 2 £1000

So if in March I run a report I will see £2000 against cost ctr1 and £1000 against cost ctr2 for emp1.

Any best practice suggestions welcomed

Steve