Groovy Scripting combining 2 Lists using .Unique

Content

We have a groovy script that identifies the Entity members that changes in a form when saved.   We will then loop through this list of changed Entities and come up with a corresponding Entity member that contains a particular attribute.  We can come up with the two lists and can combine them.  However we cannot come up with a desirable unique list.  Here are the basics areas of the code in question.

List 1  (Entity Members that have changed on a Form Save)

def LChangedEntity=[]
dataGrid.each{
 LChangedEntity << it.getMemberName("Entity")
}

List 2  (Entity Members looked up from an attribute)

def LPrimaryEntity=[]