Octave line question

Is there a trick to getting two octave lines one above and one inside a grand staff in a piano part with cross-staff notes?

I’d like to have an ottava line above the top staff, and then one between the two staves for the left-hand notes.
I know it’s not entirely orthodox engraving practice, but it seems to be the only way for me to get this measure looking readable.
I would like to keep the material separate, on two staves, to make clear that some notes are right hand, while others are left hand. I’d also rather not break the beams to keep everything on the top staff (which would give me stems up and stems down, for each hand.)

If worse comes to worst, I’ll find an alternate way of notating this passage.

Yes, you can do it by placing the caret on each staff and creating the octave line that way, rather than doing it from a selected note.