That's true about working with them separately so that they know to look to you rather than just bonding with each other. You want them independent of each other as much as possible so they can be confident alone if need be.
I have fond memories of raising Cole and Ember together as pups
...and some not so very fond memories of what it did to the backyard!
When we moved we had to relandscape the whole backyard--it was basically beaten into dead earth by puppy paws, all the shrubs were gnawed and the arbor vitae all looked like they'd been grazed by deer cuz the lower branches were pulled off.
Of course, our yard was part of a city lot, only about 50 x 75 square feet in size, so it got pounded pretty hard by the little darlin's.... Mals would be much bigger!