It’s there… in multimode choose level or pitch. Select the slice you want to alter and then Shift-B. It’s the same screen you set the multimode sync. I never tried what happens when multimode is off, because in my template all syncs are on on all parameters. Might be necessary (sync on for filter), but who knows…
The best way to get what you want and to understand how it works… is to set mmsync to on for all params. Level, pitch, envelope, slice: enter the setting with Shift-A. Plus, like I said before, set mmsync of the filter on: Shift-B in level or pitch.
Now every one of the 8 pads (slices) can have it own (independant) level, pitch, env and filter setting.
After you get whats happening, you can set some of the mmsync settings back to off, if you still want that legacy mode for some of the params.