Withholding tax setup for aggregated invoice amount for a particular supplier, for a particular peri

Hi All,

We are currently implementing withholding tax for supplier invoices based on a government regulation.

When one supplier been taken based on their transactions (Service invoice) if taken invoices aggregate the amount Rs. 50000 a withholding rate of 5% will be charged.

If within a month this does not aggregate the amount Rs. 50000 then no withholding tax will be charged.

If a year the invoice amount aggregate the amount Rs. 600,000 then 5% withholding charge will be calculated.

Ideas for implementing such requirement.

Regards,

Sayuri