Order For The Text String To Turn Into An Active Formula

When building complex and long formulas in excel which can not be auto
filled due to non progressive variables I tend to combine several cells
containing parts of the formula using the ampersand (&) operator.

E.g. B2=[A1&A2&A3&A4]
where:
A1=[=]
A2=[INDIRECT($A$1&"!"&"S]
A3=[8]
A4=[")]

The result will then look like this: =INDIRECT($A$1&"!"&"S8"), then I
copy all the values created by this method (it could be several
thousand)
and past them into the appropriate worksheet using: past special > past
values.

The problem is that in order for the text string to turn into an active
formula I have to go into each individual cell (F2) and hit Enter. When
I am working with thousand of cells this is not very feasible.