The problem of overlapping markup hierarchies, first mentioned in the context of SGML, often occurs in XML text encoding applications for humanities. Previous solutions to the problem rely on manual maintenance of the markup and address only the problem of representing overlapping features in XML, leaving the issues of automated maintenance and querying open. As a consequence, traditional XML tools are of little practical use when dealing with overlapping markup. In this work we demonstrate the implementation of our framework for management of concurrent XML hierarchies from a computer science perspective. We propose an underlying model, data structures, API, and algorithms so that the most of the burden of managing concurrent XML hierarchies would be borne by the software.