How to define a separator and how to use it using the Open Inventor path

I have several dividers, such as a table, a lamp, and a frame on my scene graph. When I add them to a separator called root, then they turn into nodes? As if I wanted to use them with a path, is there an equivalent path-> containsNode for delimiters?

Also, is there a way to identify the delimiter? Say I would like to put a lamp on a table. I think the best way is to check if the lamp collides with a specific separator, like a table?

Thank!