This is my video for the hardest achievement in Pacman. Many have failed completion due to this, And if you are reading this I guess you are stuck too.
Make sure you set the live to 5, accessed in the OPTIONS menu. The video explains all this but just so you are aware. The first two are the easiest to do as you can use a set path to get the Ghosts together the majority of the time. The last 2 require a little more luck, but using the same sort of path I take hopefully you will have this done not long after.
Enjoy the video and hopefully it helps and keeps you entertained.