As mentioned above, colonizing and releasing that area is generally good enough, though if you keep those lands to yourself they'll benefit from your superior technology. Regardless of what you do, colonization is profitable even in the poorest of places, mostly because there's no downside to it. More population, regardless of how much more, leaves you with more people that rely on your local market, which in turn increases the demand for your goods which in turn lets your factories sell more products which in turn lets them make more products which in turn allows you to support more and bigger factories which in turn increases your industrial score and makes your country stronger and wealthier. If the RGOs are utterly crap than there's no downside to releasing those provinces as satellites, if the RGOs are decent, even if they're good luxury goods like Tea and Coffee than you might want to consider keeping those colonies yourself to allow the RGO workers in those provinces to benefit from your superior tech.