treat my territory as local for ship range... us there a diplomacy option?

Maybe I've just been exceptionally unobservant, or the dotted lines just dont reflect it.. But it seems like there should be a resupply treaty type option, especially on larger maps where getting to a neighbor might take some work or specialized deep space probe type ships, but without the ability to travel to them with say... A warship fleet before the war ends, it makes simply offering support or maintaining relations difficult to care about simply because it doesn't much matter who is way over there  & finding who is way over from way over there somewhere around  the far side of an absurd undertaking

I can't much care when $race in gakcivIi asks for help in their war with $aggressor on gigantic given that I'd need to step star bases across $Neighbor  and piss them off just to -get- there with much of anything capable of putting up a fight.... But if open borders, or more specifically a second similar one allowed sharing of ranges, making contact would open entirely new doors