Fleets on the same coordinates will not engage in the same fight, only fleets standing next to each other on local coordinates - in the same " battle zone ". To be in the desired battle zone, you will need to select a fleet from that zone when sending it out (just as you now select a satellite, and only fight with fleets on that satellite).
Example targets for sending
In a dispatch, you will see which fleets are in the same zone - they will be displayed linked. Upon arrival, the fleet will exit subspace to a position at the local coordinates next to the target fleet. All linked fleets will enter the battle (if any), regardless of which fleet was specified as the target.
If there was no target, or all of the target area fleets have gone away, the fleet will take a random position in orbit, away from any other fleets. Such a fleet will not engage in any battle when it arrives at the location.

The "Transport" order will transfer resources to the selected fleet. Specifying the player's name will no longer be necessary.

Since the composition of the fleets in the selected battle zone can change, it is recommended to check it while your fleet is flying, to avoid surprises. It will then be possible to check the contents of the fleet at the destination location, either directly from the Fleet menu or from the Sending menu.