Outdoor is related to Ground. Ground is related to Drop. Drop is related to Collection. Collection is related to Bill. 
Voice is related to Neck. Neck is related to Supporter. 
Outdoor <--RelatedTo--> Ground <--RelatedTo--> Drop <--RelatedTo--> Collection <--RelatedTo--> Bill 
Voice <--RelatedTo--> Neck <--RelatedTo--> Supporter 