Gosh, just the opposite here. Mardi and Archie push each other aside to be first in line for a brush.
What type of brush are you using? Many here, including me, use a Zoom Groom. It really helps release the undercoat without damaging the top coat. I use a Bamboo brand come with rotating tines held at about a 45 degree angle to finish up.
Put Rosie on a leash. Of course, you have a youngster full of labbiness. I make it a no nonsense session, like clipping nails. Archie will get a little antsy and keep turning until I tell him to stand still.
Good luck.