The irreversible trend toward decentralized information sources makes less and less adequate the current approaches to search mostly based on a centralized index. The Constraint Based Knowledge Brokers (CBKB) model is a first attempt to provide an efficient decentralized search engine, and it does so by exploiting the power of constraints. One of the reasons of its efficiency comes from sending the information providers requests based on very specific and prefiltered information. This is done via a method which splits the scope of the broker agents as the requests come. However, an exaggerated use of scope splitting may lead tO an unmanageable quantity of agents. Techniques to avoid such situations may be based on several approaches, which we briefly describe in this paper, like scope merging based on anti-unification, organizing agents in disjunctive structures, and limiting scope splitting on the basis of the capabilities of the knowledge bases.