CMIS supports objects being "multifiled" -- that is "filed" in multiple folders -- and ModeShape has a multifilingService attribute described as being "used to file/un-file objects into/from folders" via the Apache Chemistry API. Does this imply that in ModeShape an nt:file node can have multiple parent nt:folder nodes or, if not, would one use multiple nt:linkedFile nodes for the objects and somehow synchronize their (custom) properties or reflect them in the nt:resource node, or some other method of modeling?
At this time it is not supported. How critical is this feature for you?