The best (and so far only) table to have a multiball feature is Star's Phoenix.
To activate the multiball, you must lock two balls on the same ball (progression resets on the next ball). In order to do that you first have to hit all five fly targets that spell STARS. Unlike regular drop targets, it may take a couple hit to get the fly target latched down. Once all five targets are hit and latched down to the top, flip the ball into the ramp on the upper right of the playfield, which starts at the 2nd S of the fly targets.
Repeat the process a 2nd time on the same ball and you'll activate the multiball mode and therefore pop the achievement.