[Membership 2 Pro] Discount membership automatically for other member type

I am offering two types of paid membership for my site (not live yet). One for permanent access to one-off training material (we may change or add to the material) and another for regular premium content (Gold Members).

I have currently set up Membership 2 to offer a coupon - revealed only for on the membership page for the training members - for Gold membership, and vice versa, but it would be good to offer an automatic discount/different price for members of one membership to the other.

I know you can set pro-rated upgrade paths but this is not an upgrade but a "cross-grade" (using the setting that allows people to be members of more than one membership).

If not, I'll stick to the coupons, but it's slicker and more secure (only those who have actually paid can get the discount) if it is automated.

Thanks,
Arthur