Splitting NI for 2 months work

Suggested

Hi 

I have an employee who started on 26th May but was missed off May's payroll.

So on 30th June he'll be paid £2500 made up of £500 for May and £2000 for June.

National Insurance needs to be calculate on the 2 amounts separately so he gets 2 months of NIC allowances.(NIM08310)

I can't put through pay for May and submit an FPS for May as they weren't paid anything in May.

So when processing June's payroll, how can I calculate the NI?

It's also my understanding that  the NI contributions should be recorded on the employee's payroll record for the separate tax months i.e tax month 2 and 3. How can I do that?

Thanks