We propose a generalization of the morphological annotation in Universal Dependencies (UD) to phrases spanning multiple words, possibly discontinuous. Our focus area is that of periphrastic tenses, voices and other forms, typically consisting of a non-finite content verb combined with one or more auxiliaries; however, the same approach can be applied to other morphosyntactic constructions. We present a software tool that can detect periphrastic verb forms, extract the relevant morphological features from member words and combine them into new, phrase-level annotation. The tool currently detects periphrastic verb forms in 15 Slavic languages that are represented in UD and it is easily adaptable to other constructions and languages. Both the tool and the processed Slavic data are freely available.