Would be nice to support embedding graphs (e.g. in a group) from other files (store only a link in the current file). For the beginning just a simple support of independently embedding the graph in the "master" group (somethnig like iframe in html) (later may be possible also inter-connections between graphs if requested). This way users are able to divide their work into more components, which may be useful in workflow modeling to avoid duplicate definitions of the same. It is also better e.g. for versioning, collaborating, it is a must for a big projects, etc.
