Again, sorry for the delay - been out of town.
I think you can do this with a layered staff workaround. Try this:
Staff 1
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Note|Dur:8th|Pos:5|Opts:Stem=Down,StemLength=4,Beam=First
|Note|Dur:8th|Pos:1|Opts:Stem=Down,StemLength=3,Beam=End,Muted|Visibility:Never
!NoteWorthyComposerClip-End
Staff 2
!NoteWorthyComposerClip(2.0,Single)
|Clef|Type:Treble
|Note|Dur:8th|Pos:-1|Opts:Stem=Up,StemLength=3,Beam=First,Muted|Visibility:Never
|Note|Dur:8th|Pos:-3|Opts:Stem=Up,StemLength=3,Beam=End
!NoteWorthyComposerClip-End
Note that the second note in Staff 1 is muted and hidden, and so is the first note in Staff 2. By experimenting with stem lengths, you can get the beams to overlap. Although I've altered the pitches of the invisible notes, it doesn't matter since they're only placeholders and are muted.
The layered staffs and hidden, muted note features are very flexible. You can even get an almost reasonable result connecting a run between clefs in a piano score, with a certain amount of tinkering.