You can do it the «hard way».
1.- Open your DE. For instance, Cinnamon.
2.- Check every installed application in the menu and write down those you don't want to appear.
3.- Open your File Manager (Nautilus or Nemo)
4.- Go to /usr/share/applications
(also check .local/share/applications
in your home folder) and identify the file name of the applications you don't want to appear under your present DE
5.- Open a terminal and type
cd /usr/share/applications
6.- For each application, type
sudo nano [nameoftheprogram].desktop
For instance:
sudo nano yelp.desktop
7.- Find this line
OnlyShowIn=
and delete the DE you don't want. If there isn't this line, add it and add also the DE.
8.- Repeat steps 6, 7 and 8 for each program.
N.B. This how-to will only help you with the mixing of programs in the menu.