ROC/ROD
This sounds like old style procedural separation where rates were used to maintain the prescribed standard separation.
Still used at airfields like Stornoway, where there is no airfield radar available. Two departures same outbound track.
Faster first hopefully. [Area: RSYD clearance]
No 1:climb greater than 1000 fpm until passing flight level 100.
No 2: climb less than 1000 fpm until level fight level 90.
Otherwise, using radar, specify a point by which the ac is required the achieve the cleared level.