The work we present here is in line with a novel approach to inter-organizational workflow cooperation that consists of three steps: workflow advertisement, workflow interconnection, and workflow cooperation. This approach is inspired by the Service-oriented Architecture and allows for partial visibility of workflows. Varying degrees of visibility of workflows enable organizations to retain required levels of privacy and security of internal workflows. Degrees of visibility are described in term of workflow abstraction based on Petri net theory. Abstractions are advertised in a common registry. Workflow interconnections are based on advertised abstraction matching.