Hi!
1, Terry Lingle, i understand what you are saying but cannot visualize it. Perhaps a sketch/picture will help like Michael Karas did. Thanks!
2, Joseph Hebert, You idea seems OK but it needs some experiments. (which i will do...).
3, Michael Karas, you idea will give good result but i have to do it on nearly 400 threads seperately and it will take more resources than i have. Thanks any way.

Any more ideas?
Many Many Thanks!