Integration and Collaboration
The secret lies in understanding the root need for integration. Often this need arises not as part of a planned consolidation or investment in better infrastructure, but because there is no alternative. Since most integration occurs between applications that were not originally designed for it, practical integration requires creative blending of ETL tools, EDI engines, messaging middleware, ESBs and data semantics.
You may want to look at integration problems for what they are and break them into pieces matching the capabilities of the best available technologies and with provisions for the inevitable progressive discoveries. Often it is not just application boundaries that must be crossed but also boundaries of technologies, networks and corporations.