1. A method comprising: initiating a first store operation to a cache data block stored in a first cache from a first processing node including said first cache; assigning a modified cache state to said cache data block in response to initiating said first store operation; initiating a first load operation to said cache data block from a second processing node; assigning a pairwise-shared directory state to a coherence directory entry corresponding to said cache data block in response to initiating said first load operation; wherein said pairwise-shared directory state is distinct from a shared directory state; and wherein assigning a pairwise-shared directory state further comprises storing an identity of said first processing node and storing an identity of said second processing node.