Thanks Jeordanis;
On this test I used groups to reproduce my difficulties on a simple plane;
But I often have the same with other mode on more comple geometries (except clump from guides that work perfectly).
I also use groups becaus on my final hair comb, I would like to create rebel strand of hairs by using a clamp sharp noise to create one extra group; I was thinking to push the affected hairs with a frizz acting only in this group and clump them then.
The frizz part work perfectly if if create a group /or a channel from this noise, but the clump part doesn't.
Even if the result of the strand data give me twice the same group at 2 different sides of the plane, "Attract to closest Stem" and "Preserve lenght" should prevent clumps to reach so far points.
On the second scen, i tested it on a head and as you can see, even with a channel to separate le right and the left of the hairs, it give me bugs of crossing that I always have with clumps.
