Last I recall the connections between systems were governed by the static peg board pattern underlaying the Freelancer system map. I could be wrong and there's been a way around it since the last time I toyed around making systems but to my knowledge such long distance connections wouldn't be possible. Also, in RP, imagine what would happen to Sirius if Gallia rolled in to seize the Sigmas without having to fight its way through a long distance filled with enemies.