Give discount from Admin’s cut.

Hi (again!),
I have a second question about your plugin please, and I thought it better to open a separate thread.

Is it possible to give the customer a discount, but take that discount from the Admin’s share of the sale only?
For example, on a 50/50 split, if I offer 20% discount, the Vendor still gets their 50%, but I only get 30%. It would be great for marketing.

I hope that makes sense?
Thank you again.