Adding barlines between a single-staff instrument and added staves

I have an excerpt attached for double bass, tape, and live electronics where I’d like to have separate instructions for the LH and RH of the bass at times. Is there a way to add dashed barlines between the main bass staff and the added left hand staff above it that don’t interact with the other staves?

I can imagine two options:
you could use a vertical dashed line and move it to where you exactly need it in engrave mode or you could have independent barlines for the contrabass and enter the dashed barlines where you want (you need to enter an independent time signature first in order to be able to have independent barlines).
I think you would have more control of the position using the vertical dashed line.