UMLR — Meaning of relationship between iteration clause and Lifeline.selector clau

UML2-rtf issue: Meaning of the relationship between the iteration clause and the Lifeline.selector clause.

Interactions often involve the invocation of multiple instances of the same class. For example I may want and instance of my Portfolio class to invoke the currentValue method on instances of associated Asset classes that belong to an asset category (Asset.assetCategory = Stock). This way a portfolio may assess its own value by summing up the current value of all its stock assets. To model this I want to show the same message - currentValue() being sent to the selection of assets that have the assetCategory equal to "Stock."

Does the current UML2 communications diagram notation support the following:

A portfolio Lifeline labeled theFund : Portfolio
An asset Lifeline labeled myAssets [assetCategory = Stock] : Asset
This would have to represent not one but all the asset instances that had an assetCategory of Stock
A line connecting the two Lifelines
A message with a sequence expression that looks like:
1 *[holding := 1..n] : assetValue = currentValue()

Lifelines are defined to represent only one interacting entity in an interaction. However the interaction syntax for communication diagrams would indicate that the lifeline can be "multivalued."

The need for a Lifeline to represent multiple instances for the purpose of sending a single message to all of them at some nesting level is very common.

Suggestion: Allow the Lifeline to have a multiplicity shown within brackets as with parts. Constrain the lifeline to have multiplicity one or greater. Constrain the lifeline with a multiplicity greater than one to have a selector that can, upon applying the selector, result in a single particpant.