Selecting a random element for a specific key in a Multimap
===

How can I select a random element for a specific keys in a multimap. For example:
	
    multimap<string, string> map;
    map.insert(pair<string, string>("Mammal", "Tiger"));
    map.insert(pair<string, string>("Mammal", "Chicken"));
    map.insert(pair<string, string>("Mammal", "Fox"));
    map.insert(pair<string, string>("Fish", "Clown Fish"));
    map.insert(pair<string, string>("Fish", "Ray"));

In the above, what would be the best way to get a random "Mammal"?

I know I can get the iterators for the "Mammal" so:

    pair<MultiMapIt,MultiMapIt>iterators = mMultiMap.equal_range("Mammal");
    // loop through each... and select one.

But I am sure there is a better solution... perhaps using the iterator as numbers..  
Thanks
