To test the replicability of an earlier study of the informal relationships among school administrators, researchers interviewed 16 principals of schools in an urban district in the southwestern United States. The earlier study had used unstructured scheduled interviews with 28 principals in a small city and suburban district to discover grouping and interaction patterns. That study found that principals tended to communicate most with only one or two peers, were aware of other informal grapevines, and formed guild-like patterns at the secondary level and clan-like patterns at the elementary level. Analysis of the information gathered in the current study revealed patterns generally similar to those found earlier. Informal interaction tended to parallel formal structure, taking place through verbal means in dyads and triads of trusting peers. A clan-like structure extended into the secondary principals in the later study, perhaps because of a past relationship between two specific elementary and secondary administrators. Sponsorship ties (links between principals and their former subordinates who have since become principals in their own right) seem particularly important to the grapevine structure. An important function of the grapevine was to allow principals to protect themselves and their organizations through "boundary-spanning" activities. (Author/PGD)