Java 8 creates three shortcuts on \ProgramData\Oracle\Java\javapath that point to the latest Java8 java.exe, javaw.exe and javaws.exe and then puts \ProgramData\Oracle\Java\javapath at the front of the PATH so that no matter what you do to the JAVA_PATH environment variable, you still get the latest Java 8.
You can get around this by
1) renaming \ProgramData\Oracle\Java\javapath to something else (\ProgramData\Oracle\Java\javapath8 for example)
2) creating a new javapath folder under Java and
3) creating the shortcuts that you need.
Just restore the javapath when you are done with the old versions and you get Java 8 back.