The research reported here is part of a larger project on the development of a robust dependency parsing scheme GRIP (GeRman Incremental Parsing) that uses the Xerox Incremental Deep Parsing System and provides syntactic annotation in an incremental fashion. It is shown that morphological disambiguation is a crucial step in narrowing down the search space for the correct assignment of dependency structures. Customized disambiguation rules of XIP provide the necessary computational tools to efficiently carry out morphological disambiguation for languages with rich inflectional morphology such as German. A quantitative evaluation on a German test corpus shows that application of XIP disambiguation rules in conjunction with heuristics about the syntactic context of German NPs yields unique morphological analyses in 77.08% of all cases with a precision of 98.93%. This result is achieved by a novel constraint-based approach that integrates phrase-internal concord rules and phrase-external syntactic heuristics into one uniform architecture.