Create three launchers, each for different purpose/session
Command examples:
medit -n --use-session=yes --app-name=notes_txt
medit -n --use-session=yes --app-name=source_c
medit -n --use-session=yes --app-name=web_php
Each of them will remember it's owned session (previously opened files and etc.).
Except for working directory in Pane "File Selector", bud you can make bookmarks and switch fast.