combine cells based on criteria of separate cells

I have data in cells A4, B4, D4 and E4 and a set of "selector" cells in P8-S8 on the same worksheet. What I would like to happen is if the user selects P8 (by entering an 'x') then cell G8 would equal the value of A4. If the user also selects cell Q8 then the value of cells A4 & B4 are combined within cell G8. This would apply for any combination of the user selecting cells P8:S8
There will also be a hyphen that needs to be included between the values of data from cells A4, B4, D4 and E4.

I think an example will make it much easier to understand so a sample file is attached.

That would be correct dave. It will be copied down to all rows

Cells P8:S8 will remain static and are the determining factor for the full sheet. The formula itself will be copied down the full column of G. Row G is constant as it relates to cells A,B,D & E so the result of G7 will be the data from A7, B7, D7 & E7 and so forth.

Hopefully that makes sense to someone besides me.

Try this:

Change entries in P8:S8 to 1, 2, 3, 4

in G4

=SUBSTITUTE(SUBSTITUTE(SUBSTITUTE(SUBSTITUTE($P$8&$Q$8&$R$8&$S$8,1,TEXT(A4,"00")),2,TEXT(B4,"000") &"-"),3,TEXT(D4,"00")&"-"),4,E4)

See attached with results in T8 down

John that appears to do the trick. I'll play with it a bit to verify but on initial try it seems to be exactly what I was looking for.

Thank you for the help