To show fullname when mouse over

hi, 

I have a matrix visual as shown below and i would like to show the fullname when mouse over on the name. 

for example, when i mouse over on 'a', it should display 'apple'. 

i have tried to use tooltip but seems like it is not working if it has one to many relationship. 

please advise. thank you in advance.

visual

table

one to many relationship between tables