The inter-process collaboration can be quantified as a cost based on the multiple exchanges between the web services which execute the business process tasks. This cost can be calculated by using interoperability criteria. The objective of the paper is to provide the formal definition of the resource consumption optimization problem within inter-organizational business process execution. We have defined and tested the model by studying the process of the brand image creation for a customer in an enterprise network. The results show that the overall cost of resource consumption is greater than one thus, the resources are over-used, and removing the unnecessary web services can optimize the utilization of resources during the execution of the inter-organizational business process instances.