Super node snapping

Inkscape currently has a way to snap a drawing node to another drawing 
node.  Is there a way to associate a "super snap node" with an object 
which would take precedence over the drawing nodes?

Let me give an example.  Proteins sometimes exist in cell membranes.  
The protein SVG would be a complex drawing, as would the membrane, both 
packed full of the usual drawing nodes.  So moving the protein to the 
membrane in the usual snap mode is not going to be at all helpful.  The 
"super snap node" would consist of a vector defined by two points 
specifying a position and an orientation.  It would be associated with a 
grouped object but would not normally be visible.  It would indicate the 
proper insertion orientation and position for the protein.  A matching 
"super snap node" would be associated with each element in the membrane. 
  In those mode one could drag the protein to the membrane and drop it 
and it would center and orient on the nearest super snap node in the 
membrane.  Since cell membranes have two sides moving the protein over 
to the other half and releasing it would flip it 180 degrees and insert 
it in the other direction.  In the more general case, there could be 
types of super snap nodes, so that only a pair of the same type would 
interact.

(Note, my email is acting strangely today - I'm not sure what the 
subject is going to be on this message. )

Regards,

David Mathog
[email protected]
Manager, Sequence Analysis Facility, Biology Division, Caltech