Give Different Gift Cards Based On Different Subtotal Order Using Promotion!

Hello,

I'm using cs-cart MV 4.9.3 and I want to give different Gift Certificates to the customer based on the different Order Subtotal amount like below:

For the order subtotal greater and equal to 400\$, give the customer a Gift card with the amount 20\$

For the order subtotal greater and equal to 800\$, give the customer a Gift card with the amount 40\$

For the order subtotal greater and equal to 12000\$, give the customer a Gift card with the amount 60\$

For the order subtotal greater and equal to 1600\$, give the customer a Gift card with the amount 80\$

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Generally, I have this formula for promotion:

'For the order subtotal greater and equal to n*400\$, give the customer a Gift card with the amount n*20\$' which 'n' is a range 1,2,3,4 and so on!

I could create a cart promotion and tell that if the order subtotals greater and equal to 400\$, give the customer a Gift card with the amount 20\$, or any other rule ALONE! But what about ALL rules? In this case, I must create unlimited promotions!

Is there any solution guys?!

Thanks

Armita