GREEN LANTERN: EMERALD DAWN II from 1991 (a couple of years after INVASION! itself) was a six issue miniseries that showed the early days of Hal Jordan training to be a Green Lantern under the tutelage of Sinestro. The series would show how Jordan mastered the power ring but also detailed the fall of Sinestro, once the greatest of the Green Lantern Corps.
In issue #2, there’s a short scene where Sinestro imposes his own form of order when he gets wind of the beginnings of an alien alliance . . .
The insistent visitors are Sinestro and Hal Jordan, of course, and there follows a fight scene where Sinestro insists that the alliance will not go ahead. After the Green Lanterns leave, however . . .
It’s a nice little addition to the INVASION! story.