Gray roots question

[soulshine]

Is it possible to use 10 volume developer with 9N (or maybe 8N) color on gray regrowth without it affecting the surrounding natural level 6.5 hair color? There are so many little grays sprinkled amongst the natural color. Since 10 volume is a deposit only, I was curious if I could put the 9N (or 8N) on all of the roots to have it tone the gray pieces only without it affecting the pieces that are the natural color.

I know I could do a 6N on all of the roots while also pulling out some of the pieces for the 8N and 9N highlights, but I was just curious if this was a feasible shortcut.