I slide my entire right hand/wrist...up to my forearm...right through the loops of all leashes.
Then I grab the leashes with my left hand, placing the two dogs on my left side and off we go.
None of mine are spooks or bolters, but this way, the leashes are 'attached' to me with my arm through the loops, and held in my hand.
Now I'm taking three dogs, I still have my right hand/arm through all three loops.
I hold Nigel & Ruby's leashes in my right hand and lace them on my right side and grab Nixon's leash in my left and he walks on the left.
They all walk along just fine like this.