I have also seen other players interested in being able to link groups of turrets together, so that they concentrate fire on a single target.
We not only want the ability to "group fire" (fire all weapons in a group at once), but also "burst fire" (fire each weapon in a group, one after another with a single trigger pull), and "chain fire" (fire one weapon in the group, and then auto-switch to the next weapon in the group ready to fire). Not to mention the infamous Mechwarrior "Alpha Strike" (firing all weapons at once, regardless of group).
Grouping would be an excellent way to use those extra hotbars in the ship.
As always, it would help if we could name individual weapon computers, and also that the weapons would be sorted in some predictable way (such as alphabetically by name), when assigning hotbar slots, so you know exactly which weapon is going into which slot.
To make "grouping" work, I think it should be a simple matter of being able to assign more than one computer to a single hotbar slot. Then you could put weapons 1, 2, and 3 into one slot, then put weapons 4, 5, and 6 into the next slot. Presto! Instant grouping, similar to multislots in build mode.
It would also be nice as I mentioned above, to be able to put the same weapon into multiple slots, and select which slot does which multi-weapon firing behavior (group fire vs. burst fire vs. chain fire) So you could put weapon 1 into its own hotbar slot for individual firing. Then place it along with weapons 2 and 3 into another slot for group fire. Then place it in a third slot with weapons 2 and 3 for chain fire.
Finally, it would help to be able to label each slot. That way, using the example given in the paragraph above, you could label the first slot "weapon 1 fire", the second "group 1 fire", and the third "group 1 chain". Or whatever label makes sense to you.