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Just referencing the geometry would be fine.
Please note that referencing .rvt files (which can be very large) will probably be very slow, and require a lot of settings. It would be good to be able to set up an .ISM or i.Model type file that a Bentley user would be able to reference without complete conversion.
Same problem with .ifc files which can be referenced already, but very difficult to use... for large files.