Halliday & Matthiessen (1999: 244):
… instances of grammatical metaphor do not typically occur in isolation. When we find grammatical metaphors in discourse, they nearly always cluster into what we are calling syndromes; these are typical clusterings of metaphorical effects among which there is some kind of interdependence (for example, in the government decided => the government's decision, there is an obvious relationship between decide => decision, process as thing, and the government => the government's, participant as possessor of the thing). Nevertheless there are two metaphorical effects here, not just one; and they have been treated separately …