Key propagation

[franv]

I was wondering if it is possible to limit key propagation, that is the number 
of times a key can be exported and reimported.

If I understand correctly, once a key is created, there is no way to limit the 
number of times this key is going to be propagated.  If I give my public (or 
secret for that matter) key to someone else, that person in turn can export it 
and give it to someone else, ad infinitum.
 
If I want only 1 or 2 other people to have my key, is it possible during the 
key creation to give it a parameter stating that this key can only be exported 
x number of times?

Of course all this assumes that I still have control of the key file, for 
instance I go on the other person's computer, import the key and then delete 
the original key file that was used for the import.

Thanks