Making only some staves in a score invisible

I have a simple score for single line which I have formatted over four lines, four bars/measures per line.

I want to make the staves for the first two lines invisible but keep them for lines 3 and 4. I can't work out how to do this! I've tried highlighting the first two lines and going to 'Edit' and checking the 'Visible' box but it applies this to the whole score instead of just the two lines I've selected.

Can anyone help please?