Unfortunately you cannot do what you have in mind using the online button creator as it does have limitations. You would need to manually code your item button using a combination of the discount variables and a custom script to manage the logic. Both the button code and script would reside on your web page or site. See the tips below for using the discount variables. As for the script, if you're not into coding your own stuff, you would need the help of a developer. Note, there are also 3rd party shopping carts that may have the type of features you're looking for.
Here's some important stuff to be aware of. The Discount Variables listed below are intended to work with Buy Now Buttons and Add to Cart Buttons. They only apply to the item they are associated with, "not" the entire shopping cart. This means that you can "only" apply a Discount to an individual item and they do not apply to Taxes or Shipping.
discount_amount
discount_amount2
discount_rate
discount_rate2
discount_num
Tip: To use the Item Code Discount Variables with "hosted" or "encrypted" item button code, you need to modify button code using the "Advanced Variables" in Step 3 of the online button creation process. Look for the text box near the bottom of the page. There you can insert extra variables. For example, you want to offer your customers a 10% discount on one particular item regardless of the quantity of that particular item. Simply insert the "discount_rate" and "discount_rate2" variables in the text box. Just enter:
discount_rate=10
discount_rate2=10
There's no HTML extras, just the name of the variable, an equal sign and the value.
The following Discount Variables will only work with the "Upload" Method.
discount_amount_cart - Applies to entire cart. **
discount_amount_x - Applies only to the individual item.
discount_rate_cart - Applies to entire cart. **
discount_rate_x - Applies only to the individual item.
** Note: These variables will be ignored if you are including any individual sales tax amount or rate in your upload code. This is because the sales tax needs to be calculated after the discount is applied to your items therefore, the discount is applied to the item Subtotal, not the Total. In addition, the discount does not apply Shipping.
