Based on the fire rules can the following storm trooper squad of 6 folks armed with 1 HH-12 and Concussion Grenades do the following, using split fire in one fire action:

1. Have the HH -12 dude shoot at a unit

2. Have 2 of the 5 remaining dudes shoot blasters at another seperate unit

3. Then have 3 of the remaining dudes throw grenades at yet a third separate unit

So in sum the unit has targeted three different units.

Is this a correct reading of the rules?

3 different named weapons, 3 attack pools all formed at the same time is allowed

Yes this works.

This is correct.

How else could you have a squad of your elite Stormtroopers fight off an entire army of Rebel scum?