Going "up" a tree is typically a bad idea, for the simple fact that the system must work on the assumption that there might be more than one parent. You can try appending .Parents but it might return multiple ones.
A better idea is probably to start your filtering directly at the parent level, and then look at the descendants of the selected parents. This might have the side-effect of having to edit the Text8 property on fewer members, which is always a good idea.
