Hmm, yea, my suggestion is baiting them to pass right over the wormhole you're coming from (possibly by sending a transport and unloading some units sufficiently far away), and slamming them with lightning-missile-in-the-face when they do. Rinse, repeat
Or distract them in some other direction and sneak a force through to the other side. Or distract them and pop the command station with a lightning/armored missle or something (I forget if some station variants are immune to that), and the defending hybrids will generally disperse to take other missions.
But wow, 145
It makes sense since a single AI's population cap for hybrids on a large map is typically in the 70-110 range (planets / 5 + spawners * 4, so say 120 / 5 + 20 * 4 = 24 + 80 = 104), and since you've got them both on. Also, 4 hours sounds like it would be just enough, since the spawns take about 25 minutes, and 240 / 25 > 9; 9 * 20 = 180. This is assuming roughly 20 MkIV/Core/Home AI worlds, and you probably actually have more than that. One thing that isn't immediately obvious about higher-planet-count games is that they have a significantly higher percentage of IV planets
But yea, this is a good example of why the defending hybrids should have some logic for switching to attacker-types when they've got the humans completely choke-pointed. Strategically speaking it's probably wiser to camp the system with 145 hybrids (it's not much different from what a lot of human players do), and they've basically won the game by doing it unless you can pull off something pretty impressive. But it would be more interesting if they would take the offensive and make your loss quicker and hopefully more fun
Also should probably tweak the spawner seed amount down from 1 per IV/Core/Home world, and then multiply it by the number of human player/homeworlds. Ironically we're simultaneously getting situations like this one where the hybrids are roflcamping (or roflstomping) single-hw players but are providing inadequate challenge in multiplayer