Originally Posted by
Radscorpion
Yes it is possible. What you can do is this:
Edit the startpos... Make so every faction has their capital set to some distant region they most likely won't get to (like the Black Hills in the Americas).
Now every faction should lack a capital. Meaning you can buy off any of their regions. The faction won't get destroyed.
Note: I did this within the Imperial Destroyer mod and made all factions capital be Indonesia. This worked. Maybe it only works with this region, but you can still try it. Try one faction first to see if it works.
Of course, the downside with this is that no faction can have revolutions since they lack capitals.