How to find cells within a distance
 

Hi Foamers,
I need to find, given a cell in the mesh, the labels of the cells within a given distance. Now I do it sweeping for all cells all the other cells and saving the ones that are nearer than a certain length in a labelListList, but this procedure is clearly heavy. Is there anything in OF that could help me to do it in a faster way?
I was managing to do it with mesh.cellCells(), but I can't find a way...
Thanks!!!
Ivan