Combining set number of products from existing items?

I have a set of 8 products. Each product can be bought separately but there are 2 bundles that can be bought for a discounted price.
The bundle of 8 products is easy to display because the customer receives all 8.
But what’s the best way to display 4 products for a discount with the option for the customer to choose 4 products from the 8 that are available?
Thanks for any help