How do you create this effect?

Hi all, I have a harmony backing vocal part I'm struggling with. It's 4 beats, first note comes in on beat 1 and lasts till the end of beat 4, second note in on beat 2 last till end of beat 4, third note on beat 3 and fourth on beat 4, all lasting till the end of beat 4. This then repeats 4 times. 
 
I'm trying to create something similar to what is heard at about the 1:04 mark on this track - https://www.youtube.com/watch?v=Tqn3femtNWU
 
Has that sudden impact with each note. I've assumed it's some kind of side chain compression? I've tried using Waves C1-SC but with no such luck. Any ideas? Cheers.

Rick O Shay
CPFC,
 
Are you talking about the same kind of thing that happens here at 1:13?
https://www.youtube.com/watch?v=nlcIKh6sBtc
 
If so, that's pretty much just a bunch of multitracked vocals.  With each successive note that is added, the other voices hold out their notes and by the end, it's a nice big fat chord.

Kind of like that Rick, although the Lordes part sounds a lot more natural. The Bright Eyes part seems to have more of an initial impact with each note that comes in. My part is more akin to the Lordes where each part comes in and builds a chord, but I'm struggling to create that initial impact part. May it's because it's starting with a 'B', just hits you harder than 'a', 'e', 'i' etc.