Consider the following set $A$ that contains $N$ subsets of cardinality $K$. In this example, N=4 and K=3:
$ A=\{\{5, 10, 8\}, \{1, 10, 4\}, \{6, 12, 2\}, \{3, 3, 10\}\} $
I would like to write an expression that considers only the subsets of set $A$ which contain a specific value $x$. For instance, if $x=10$, then the subsets $A_1$, $A_2$ and $A_4$ should be considered because they have at least one element that has a value equal to $10$.
Thanks in advance.