I'm having some luck manipulatng with the morphbrush tool, but it's hard to get exactly the desired parts as the computer slows way down while selecting.

With magnets I selected tongue (the new group) in the group for mag zone properties.  The magnet still doesn't change the tongue.  In magnet properties the new group "tongue" isn't available in the "add elements to deform" sub menu.

It seems like magnet would be easier, but it still won't effect the tongue.