I am using the countif function to count all of the cells in a column
(O11-O24) that have the value "x."

=COUNTIF('Remote Offices'!B1:B5,"x")

I want to modify the formula, so that it returns to me the text in a
different column (A1-A5) if the condition is met. Is this possible?

For example if cells B1, B2, and B5 have the value "x" and cells
A1="Irvine", A2="Anaheim, and A5="Tustin", I would like the function to give
the following result:
"Irvine, Anaheim, Tustin"