duplets in 9/8 time six notes total.

I am trying to transpose a sheet of music for my high school band changing a tuba part to a bass guitar part. I have come across four measure that require duplets with six notes and for the life of me, I can not figure out how to get those six notes copied to the sheet music without a rest showing up or the notes going to the next measure. o-o o-o o-o that is the rhythm of the measure. Can anyone please tell me how this can be done. I have tried using eighth notes, quarter notes and even whole notes and nothing will fit in correctly.

Sharol