One of the key challenges of architecting electronic record sharing solutions that are scalable and can provide acceptable performance is how to create a longitudinal record for a patient when the desired data will be stored in several distributed point-of-service systems. This paper will review the design and standards selection process that has been made by Integrating the Healthcare Enterprise, a multi-national collaborative of care providers and developers that analyzed a variety of approaches. In particular, the requirements, issues, and alternative solutions for scalable, standards-based data locating services supporting regional and national health information exchange solutions will be discussed. Guidance will be offered to architects of regional health information organizations to take advantage of this experience and leverage the IHE Technical Framework, its testing processes, and tools to accelerate their projects and facilitate the interfacing of EHR systems serving different care settings from different vendors or developers. The implementation experience in 2005-2006 of the IHE Integration Profile specifications supporting an interoperable RHIO solution among various EHR systems from more than 30 vendors will be analyzed, with key lessons summarized.