Aha, sorry !
I do have 2 Actions for that in my Reaper Action List:
Script: Move to next item edge on selected tracks.eel
Script: Move to previous item edge on selected tracks.eel
Problem is that i dunno anymore if these 2 are automatically installed when you have installed Reapack (
www.reapack.com).
In other words, i can't identify from which script developer these 2 scripts are.