What I suggest and will try to implement in my game...
Or just use rules as written.
Take one attack with each weapon, two different targets. Don't forget recoil and offhand modifiers. Split the pool in two. The two targets avoid and take damage as normal.
With the addition house rule that you let the shooter use both weapons to attack the same target twice.
Don't forget recoil and offhand modifiers. Split the pool in two. The target avoid two individual attacks and take damage from two individual attacks.
When using two weapons against one target you can judge that it is also OK to Take Aim.
- which make it easier to use two weapons against one target than using two weapons against two targets.