Just cut and delete the bar(s) of the drum loops that you want to get rid of. Or just Mute them.
Cut out or mute the midi notes in the midi drum track.
Automate the volume drops in Reaper ( if Reaper has automation )
Can you give a sorta detailed example or perhaps a youtube of a song that might have such a thing going on? If its like Dance music, then Automation is REALLY helpful for the dropouts.
Reaper should be fine FL Studio, Ableton, etc..etc.. should easily do this.
You could also setup a midi controller say with a foot controller, to setup the Automated mutes. Use the controller like a HUI or similar to control Mute or vol fade or whatever...this way, you can stop it by your foot.
Theres a great example of this by a bass player, I forget his name but its cool.
"As for my technique, I cup my hand below my nuts,...." - tasybasslines