'groove~' reversed playback without changing playback position?

Hi, I've been trying to build performance system which has the feature of manipulating playback speed in real-time.
I can slow down or reverse playback speed of 'groove~', but then playback position jumps around.
With slow playback, I could achieve what I want by linking the 'groove~' to transport and manipulate the transport's BPM, instead of 'sig~'.
But with reversed playback, I still cannot find a solution. When sending '-1' signal, the playback position jumps to the opposite point of the buffer (ex. 0.1 to 0.9, or 0.7 to 0.3).

Thanks a lot for your advice in advance,
Masa