I have got this TEC fleet, and I've got this Ankylon Titan with its great group shield.

But do the ships stay under the shield? Nope. Even at the tightest formation, they form on a line, which extends beyond the Titan. Sometimes the Titan is on one end of the line and my ships (especially the capital ships) are on the other end of the line. Can I force them to go back under the shield? Nope, because they have their assigned fleet position and they want to return to that position.

Also, the heavy cruisers in my fleet still want to fly away and leave the group shield to engange targets.

What I would like is a Titan-tight formation, where ships always stay very close to the Titan and don't engage any targets on their own. Their only function is to stay close to the Titan and shoot anything that's in range by accident.

The fleet as a whole should still be able to engage targets, but let's leave the actual target-finding to the Titan to keep things simple. The Titan seeks targets, the rest just follows and stays close.