We used Monte Carlo computer simulations to determine the properties of grafted polymers that contain attractive functional groups ("stickers") on the free ends of the chains. By varying the number of stickers and the grafting density, we isolated conditions that drive the chains to aggregate into clusters. We also observed that the attraction between the stickers effectively "pulls" the chain ends from the bulk of the brush and localizes these sites to the top of the grafted layer. The results provide guidelines for tailoring polymer brushes that display enhanced adhesive properties.