I have no idea! You "could" pitch shift, but you'd need Maj, Min. 7 chord samples....
In GB, just open the keyboard & type the 3 or 4 notes from the keyboard ( You can use the qwerty too ) If you want, you could save them, as C /// Am /// F/// G7th/// or as a I///VI///IV/// V7/// in C...
Sounds like you want band in a box... I dunno if they even make it now... Sorry