Quick hacked 'group origin' concept

-- The overall group (this could represent the scene.view in storyboard)
local sceneGroup = display.newGroup()

-- Your group, where everything resides
local gameGroup = display.newGroup()
sceneGroup:insert( gameGroup )

-- Create some items within it
for i = 1, 10 do
    local rect = display.newRect( gameGroup, math.random( 0, 430 ), math.random( 0, 270 ), 50, 50 )
end

-- My first quick attempt at the 'change origin of groups'
local function setGroupOrigin( group, x, y )

    -- Store parent
    local parentGroup = group.parent

    -- Create in-between group and offset
    local topGroup    = display.newGroup()
    local bottomGroup = display.newGroup()
    group.parent:insert( topGroup )
    topGroup:insert( bottomGroup )
    bottomGroup:insert( group )

    topGroup.x    = x
    topGroup.y    = y
    bottomGroup.x = -x
    bottomGroup.y = -y

    -- Return the new group
    return topGroup, bottomGroup

end

-- Change the origin of the group to the middle of the
--gameGroup = setGroupOrigin( gameGroup, 240, 160 )

-- Now set it rotating
local function enterFrame( event )

    gameGroup.rotation = gameGroup.rotation + 5
    gameGroup.xScale   = 1 + math.random( -10, 10 ) / 100
    gameGroup.yScale   = 1 + math.random( -10, 10 ) / 100

end
Runtime:addEventListener( "enterFrame", enterFrame )