Assigning Cahn-Ingold-Prelog priority numbering rules for 2 groups I was asked to draw the perspective formula of


  $$\ce{(3R,4R)CH2=CH-CH(CH3)-CH(CH3)-CH2-CH3}$$


Then I had to assign priority between the two groups:


  $$\ce{-CH=CH2}$$
  and
  $$\ce{-CH(CH3)-CH2-CH3}$$


Actually, they are bonded to the same atoms until the end of the first group, but one of them should have priority over the other.
Can please someone help?
When you've reached the end of your first group (after resolving the double bond), you're next comparing no atom (on the ghost C connected to C2) to a hydrogen atom (on the 4-methyl group), and any atom has a higher priority than no atom, so your second group gets the higher priority.