•System Architect does not offer a purge/remove prompt on deleting lines, so you must edit the definition directly to remove unwanted connections, or drag an unwanted connection to duplicate an existing connection before invoking refresh to remove the duplicate.
•System Architect prompts on deletion of a line as to whether the definition should be removed. If the user answers yes then because all of these relationships are held by the one definition they all go.
•The relationship definition represents all of these relations together; all inputs to all outputs and so you get a line for each, directly from each input to each output. Users can employ individual relationship definitions to group certain inputs and outputs together. Users could hide unwanted lines but then the model is not a true reflection of what is on the diagram.
This is similar to the use of a central node with two listof-type references on which implicit lines are based. The difference is that with the above you only need the endpoint nodes and the relationship lines and with this you have a central node in addition to the endpoint nodes and the user must draw each relationship either from or to the central node, and possibly switching between line types as they do so.
Other cases
Use the above in combination with go-between nodes. For instance, a central node with 2 explicits or 2 implicits was a pattern that was used for UML 2.5.