FixVersion Listener or scripted field needed

[Scott Federman]

I have a project with two issue types

• Initiative
• Feature

A fix version is submitted at the feature level and then linked to the initiative. I need the initiative to capture the the feature release in the fix version. The problem is if there is more than one feature with different releases, how would I prepend the fix version field in the initiative to automatically capture the different versions instead of over writing?