I would like to define the node distance so that this distance is between the south and north of the nodes and not with respect to the center. More precisely
Image generated from
\documentclass{standalone}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\node[text width=16cm] (A) at (0,0) {some text, some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text};
\node[below of=A, node distance=8cm, text width=16cm] (B) {some text, some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text};
\node[below of=B, node distance=8cm, text width=16cm] (C) {some text, some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text, some text, some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text,some text};
\draw[red, very thick] (0,0)--(0,-8);
\draw[blue, very thick] (1,-1)--(1,-7);
\node [anchor=east, text width=6cm, red] at (-1.5,-4) {Distance between nodes is defined by the center, in this example it is 8cm\\ \verb|\node (A) at (0,0) {some text ...};|\\\verb|\node[below of=A,|\\ \verb|node distace=8cm,...] (B) {some text ...};|};
\draw[red, very thick] (-1,-8)--(-1,-16);
\node [anchor=west, text width=6cm, blue] at (1.5,-4) {I would like to set the node distance value as the value between the distance from the south of node A to the north of node B};
\draw[blue, very thick] (1,-9)--(1,-14);
\node [anchor=west, text width=6cm, blue] at (1.5,-11) {So that it is possible to make the next nodes have the same distance between the south and north pole, even if the text increases or decreases in size. In this example, the distance has decreased};
\end{tikzpicture}
\end{document}

