Task attributes, like instruments and vocals, should lead to split relationships, rather than be kept on new split relationships. This is needed for STYLE-2445 to lead to results that make sense.

If we add a new "member of" relationship with attributes "task: dancer", "instrument: piano" and "vocals: lead vocals":

• Currently, we end up with two split relationships, "task: dancer and piano" and "task: dancer and lead vocals".
• We want to end up with three split relationships, "task: dancer", "piano" and "lead vocals".