How do I define a set of statements of the form x∈A in set builder notation?

Question

I would like to define a set with set builder notation where all elements are of the form "x ∈ A." For example, with a set B = {x ∈ A, y ∈ A, ... , z ∈ A} it would be tempting to define B as B = {a ∈ A | a ∈ A} but in this case "a ∈ A" is just taken to mean "a" which is an element of "A" so it would be that B = {x , y, ..., z} which is not what I want. How would one define a set of statements, such as B, in set builder notation without making it misleading?