Export curves that are near a point.

Hi.

I think this must be pretty easy, but I can't find the way to do it.

I have several sets of curves that becomes from the intersection of a plane with a unique mesh (see pics). Each set is around a point or node, but is not associated to this node. I can export each set in a independet dxf file (using the magnificient FabTools plug in) and there is no problem for this.

But I want to add a number to each set, for engraving. This number is associated to the node, but the other set of curves not, so I can't make a dxf file containing the set of curves that is located in each node and the correct number of it.

How can I do it? Thanks in advance!