Because the jump ship has to pass through itself there is no "park it on this side and other ships go back and forth." Standard transit is just a game short cut for the sake of player convenience. It saves you having to split up your forces for squadron transits and to re-transit the jump ship between each ferry job, it also removes the scatter and the time you need to get the tender back to the jump point.
In a squadron transit: the jump ship also transits.
What is actually happening when you use "standard transit" and the tender can't jump all the ships in the group is that the jump ship forms a squadron with some ships. Then those ships jump through, the jump ship jumps back and forms a new squadron with the remaining ships and that new squadron jumps through and then the tender jumps back. You should only use standard transit on jump points where no threat can exist and where the saved time is not of any real significance.
A tender with a jump engine that can't jump itself can't work...or better put, should not work.
