Automatizing the merging of knowledgebases is an important step towards more efficient knowledge management. The cases when two knowledgebases need to be merged completely into a monolithic result, however, are relatively rare. Most often, some of the information is irrelevant, not trusted, or needs special treatment as a belief, opinion or preference. This paper presents an approach for partial merging of semi-structured knowledgebases. The merging scheme is based on the partitioning of the knowledgebases through the use of swimlines and the application of specific primitive merging algorithms in the partitions thus created. This approach allows the participants of the merging operation to specify their intentions in the merging process in an efficient and intuitive way.