Apply Join operator on each Attribute

Hello everyone,

As usual, I'm sorry if the question has already been posted before - although I carefully checked...

Here is my issue. I have an Example Set_1 containing an attribute called Date, and a variable number n of attributes called People_1 to People_n. I also have another Example Set_2 containing a list of names and biographic datas.

In order to get for each date the biographic datas of each people involved that day, I would like to apply the Join Operator to each attribute People_i (i=1 to n) using their names as Key attributes. 

For now, as n is still small (7), I can do it by hand, parametring 7 Join Operators for each People attribute, and joining my 7 resulting sets in the Append Operator. But, I would like to get the same result automatically, in case of n becomes too big (parametring 40 Join Operators and connecting all them to an Append seems quite heavy and inelegant to me).

I've tried during past week to find an elegant solution to that problem, and I haven't been able to figure it. I've tried Loops of all kind, Subprocesses, etc. It seems very simple though, but I've been unable to get my "hand" results automatically.

Here are some of my datas to help you.

Thanks a lot, as always :-)

Sylvain