Looking for this two or three book series I read as a youth.
Background: Humans found a way to point to point transfer in the galaxy due to force lines. Humans colonized a few systems. Lines of force changed when a local star went nova stranding the colonies.
Setting: Colonized world after the supernova.
Combined plot through series: Colony thinks it has found the re-aligned points in the point-to-point network and want to test it. Male protagonist must work with the female protagonist (named Bethany) who is the daughter of the last earth officer/ambassador/official in command of the orbiting jump ship. They are able to get it to work and are able to jump to a system where the colony has been wiped out by an attack(?). They are then able to determine that another jump point exists in this system and are able to jump to a third colony.
Here they surprise the humans who were not expecting these visitors. They are intercepted by royal forces (local colony has set up a monarchy) which are armed to the teeth. They find out that the new colony has been fighting against a species known as the hegemon/hegemony. The hegemony may have come in book one, I am unclear. Together the colonies determine that they can try to get to Earth because they have developed the necessary shield technology to use the jump point still somewhere in the local system that went Nova.
They eventually get to Earth where they find that the humans are fighting a losing battle against the larger and more equipped hegemony. The main protagonist realizes that the reason they are able to support such a war is that they have a larger jump network and have specialized means of production for items in specific locations then use the ease of transfer of their larger network of transfer nodes. He realized the only way to win are to take out the systems containing 'choke points' for the hegemony supply lines.
Some other things of note:
Part of the cultural/racial history of the Hegemony is that they see novas as a bad omen. In their distant past a nova caused hardship and death of young. The new nova in the story's timeline has the whole hegemony wanting to eradicate humanity as they are targets of the bad juju nova omen.