Can I make a row out of a Column?

[NCD]

I have a Product Table and a Size Table.

I have a column in my Size Table named Amount Per Size.

I have a column in my Product Table named Total Amount.

And my App Formula forTotal Amount is;

SUM(SELECT(Size[Amount Per Size], ([Product_id]=[_THISROW].[Product_id]),FALSE))

Now, what I would like to do is put this Total Amount back into my Size table as a row.

How can I do this?

[bonameblisto]

put this Total Amount back into my Size table as a row

As new row in table Size?

And what Product_id you prefer to assign for that row?

[Yogi_Hayate]

What goals do you aim by putting total amount back as a row? Could you explain a little further?

[NCD]

@bonameblisto & @Yogi_Hayate 

Thank you for your reply.

I think I found a way to do this.

I just decide to create a ALL sizes row that has the total amount of sizes.

But I don't want this to ALL to show up in my Product table. 

So my next question is how can I 

SUM(SELECT(Size[Amount Per Size], ([Product_id]=[_THISROW].[Product_id]),FALSE))

and - ALL with an expression?

[NCD]

Think I've found an easier way to explain myself.

Let's say there are 4 costumers.

costumer 1

costumer 2

costumer 3

costumer 4

and each can buy many products.

But I also want them to be able to buy products as a group.

Because I don't want go in to each customer column to buy what they all need.

I want to be able to calculate each costumer * product

and also

group * product

And also I want this to be counted as 4 customers, but now I get 8 because 4 customers + (group which has 4 customers)

How would you go about this?

[Yogi_Hayate]

Pardon,  correct me if I am wrong. So you are planning to sum total price with two columns (Group columns contains of two or more people & each customer) into one row?

Example 

Group A : Cust 1 + Cust 2
Group B : Cust 2 + Cust 4

So the total Amount of Cust is  [Total Value Group A] + [Total Value Group B] + [Total Value A]

Could you screen shoot/snipping tool your works?