I seem to be having a bit of trouble with this, actually. I attempted to make a map with interstellar connections through wormholes, using the method you explained, but it seems to corrupt my game (it won't start up). I have tested and retested and made sure that it is actually the interstellar connection addition to the notepad, and so far, the map without that section works perfectly fine. I've done a few tests already to make sure that it wasn't simple carelessness, and will continue to do so, but I'm curious as to if you can clear up a few things for good.
A) The "Interstar connection count", does that refer to the actual amount of connections, or to the star systems that are being connected? (In my map, I have three wormholes of one system connected to three wormholes of another system, so would it be one interstar connection count, or three? [I put three, didn't work. Tested with one, still no good]) My feelings are that it doesn't, but a possibility.

Do the interstar connections count towards the regular "connectioncount"? (Twenty normal connections, plus these three interstar connections = 23? [I did not add to the normal count, and have yet to test whether adding to the normal count would change the outcome]. Once again, I do not believe this to be the case, as they seem to be two separate, albeit similar, groups of values.
C) Are there restrictions on what can be interstellarly connected? (In my map, I have two identical star systems in the same location [I tested to make sure that this wasn't the problem under normal conditions {without interstellar wormholes} and have found that the game loaded fine). Due to the fact that a star system is specified in the wormhole, and that without the interstellar wormhole addition the game loads fine {the overlapping itself is not the problem}, I doubt that this would affect it [tested it just now to make sure... for some reason, when I modified the position by 1 (practically on top of it), it was ok, but when I separated the star systems completely, the game no longer loaded properly once again. On a side note, when I went into the game section to play this map after loading correctly, it could not be found (even though my other modified maps were there).
E.I.[Extra Info]) I'm sleepy (yay for overnight modding!), chances are I'm not being thorough enough. I'm also fairly new at this, so I probably made a stupid mistake somewhere.
Yes, I'm a noob. --"
Parenthesis are your friends.

-Pyre