I think you can just unify intercept location generation. Just go through a list of planet prototypes and create an intercept location for it, then change any connection that goes to current planet to intercept instead. Distances can be just 1000 for example and tweaked through settings (dynamicly generated too). You can also make a blacklist for the intercept generation loop, so any blacklisted planets (if some mods using custom planets for something but it doesn't need an intercept) will be skipped.
