Separate beaming

I'm currently trying to compose a piano piece and I'm having a bit of trouble with beaming.One part of my work the melody is played with the thumb of the right hand and finished with the left hand. However, the harmony is being played with the pinkie and ring finger of the right hand. The melody is in 8th notes but The harmony is supposed to be played as 16th notes almost an octave above the melody. How do I transcribe this without the stems combing with the melody and making the whole part of the staff connected and making the whole thing be played as a 16th?