I'm lumping these three together because, as it turns out, they're all on the same album! Or, at least, they were on the same album initially. US #18 is "Team Purpose," US #19 is "Constructions," and US #20 is "Forcefields." All three songs were composed by Sonoton regular John Fiddy and Sonoton founder Gerhard Narholz (under the familiar alias "Sammy Burdson"), and they were originally found together on Sonoton LP SON 246 (Industrial Themes & Underscores, Vol. 5). I never encountered these tracks during my original Sonoton listening run several years ago, though, because they were not ported to CDs or streaming until much later. Team Purpose & Constructions eventually transitioned to CD on SCD 442 (Corporate Classics) in 2000, while the original version of Forcefields has never—to my knowledge—made an official move to digital. There is, however, a remix of Forcefields included on Sonoton Vanguards SCDV 510, which was released in 2015. The remix isn't a whole lot different; the synth rythym ostinato (prominent at the beginning) is louder, and the tempo is a smidge slower.
I don't know of an official source for the original version of Forcefields, though you could probably find an LP rip of SON 246 if you look hard enough. The other album links (including the Forcefields remix) are included in the original song posts linked below. Special thanks to Craig-UK for finding all of this.
A mini-milestone was also achieved with these three identifications: the Sonoton Era of NFL Primetime music (1989-90) has been fully identified! At least, I think it has. I haven't seen every single episode of the show from those two seasons, but every song from every highlight I have seen is ID'd.
LINK - Team Purpose
LINK - Constructions
LINK - Forcefields