This paper deals with combination and development of individual resource units that are embedded into networks of other units. The aim of the paper is to analyze the possibilities for a supplier and a buyer to limit the change boundary when adjusting their resources toward each other, and thus to predict the total outcome of a certain change. The paper is based on a case study on implementation of ERP (enterprise resource planning) systems. The case focuses on a Swedish ERP-supplier’s development of a customer specific solution in interaction with one particular buyer, whose requirements could not be met by existing product features. The buyer is a subcontractor on the second tier in the automotive industry and implemented the ERP system in order to improve the coordination of certain sequentially dependent operations. The case reveals four different ways in which a supplier and a buyer may try to limit the change boundary, each of them associated with certain problems in predicting the total outcome of a specific change.