Problem in calculation of GTA.

In GTA Calculation the service tax has 2 scenarios:

1) Duty to be calculate on 25% of invoice value if the invoice value is more that 1500, in case of common delivery by the freight vendor.

2) Duty to be calculate on 25% of invoice value if the invoice value is more that 2500, in case of Individual delivery by the freight vendor.

Same vendor (Transporter) may be provide common delivery or Individual delivery.

How to handle this scenario in With holding tax.

Regards

Kiran A