Copy a range to the next blank column to the right

I need a macro that copies a range of [changing] values linked to other sheets, say, range B3:B20, to another range beginning at R3, if empty and for the first copy iteration.  Then copies B3:B20 to S3 for the second iteration so as not to overwrite previous copy iterations, then to T3..., etc., etc.
Code [needing capability for progressive copying to a next empty column to the right] follows:

Sub Copy_To_Trend_Visual_Aid  
 ActiveSheet.Unprotect    ' unprotect sheet
 Range("B3").Select      ' start at cell B3
 Range(ActiveCell, ActiveCell.End(xlDown)).Select  ' select range of contiguous rows
 Selection.Copy                              ' copy the range, say, B3:B20
 Range("R3").Select                       ' go to cell R3 [the first blank column to begin successive  copy iterations]

' { code needed here: move cursor to R3 and pastes range B3:B20.  If R3 is not blank [already used/occupied], select the next-to-the-right empty cell from R3 and copy to, say, S3 [or any next blank cell to the right]. On successive copy/paste iterations seeks next unused /adjacent cell to the right, e.g., T3, U3, V3 ..., etc. }
 
 Selection.PasteSpecial Paste:=xlPasteValuesAndNumberFormats, Operation:= _
        xlNone, SkipBlanks:=False, Transpose:=False    ' pastes values & CF
 Range("a1").Select                                                       ' park cursor in standard location
 Application.CutCopyMode = False
 ActiveSheet.Protect DrawingObjects:=True, Contents:=True, Scenarios:=True   ' protect sheet
End Sub