If the information is contiguous and you have empty cells around the
final sort  grouping, you could use the CurrentRegion property. This
selects the group of cells around the selected cell up to the first
empty row and first empty column. Search for CurrentRegion Property
in VBA Help.

Thank you for your suggestion, but in fact that doesn't fit the
grouping of the relevant cells. They are all contiguous, but not
surrounded by emply cells--so, in effect, it is only one part of a
larger block. In the present data  set, for example the entire block
would go from A1:N141, but the needed selection for the formulas is
E2:N141 . . . and the next set of data might have a different number
of rows, so I have a counter set up to check. I can get the correct
address for the block to show up in a MSG box, using the variables
from the counter, but I can't figure out the syntax to put that in
as a range to select for the fill down. There may be another way to
do this entirely, so I'm open to suggestions. Since I'm new to
Visual Basic, I might be overlooking something very simple.

If you can display the range you want to select in a MsgBox, you are almost
there.
Here is a sub with 2 examples of displaying a range in a Msgbox, then
selecting that range.

Sub AAAAA()
'Declare variables
Dim Row1 As Long, Row2 As Long, Row3 As Long, Row4 As Long
Dim Col1 As Integer, Col2 As Integer, Col3 As String, Col4 As String
'Assign values to variables
Row1& = 1
Row2& = 21
Row3& = 11
Row4& = 31
Col1% = 2
Col2% = 7
Col3$ = "E"
Col4$ = "I"
'Select using numerical column references
MsgBox "Range(Cells(" & Row1& & "," & Col1% & "), Cells(" & Row2& & "," &
Col2% & "))"
Range(Cells(Row1&, Col1%), Cells(Row2&, Col2%)).Select
'Select using alphabetical column references
MsgBox "Range(" & Col3$ & Row3& & ":" & Col4$ & Row4& & ")"
Range(Col3$ & Row3& & ":" & Col4$ & Row4&).Select
End Sub

YES!!! . . . THANKS YOU! at least My initial attempt to apply this
sub with my variables worked fine. I'll have to test it out on
several to be sure, but I think I understand what I was missing
before.

Set a variable to get the address of the deleted row (strStart). Set
another variable to get the end of the selection (strEnd). The set
your range using the two variables as the start and end points.

I just tested the example below.

Sub SortRange
Dim strStart As String
Dim strEnd As String
Dim strSheet As String

strSheet = ActiveSheet.Name

strStart = ActiveCell.Address

strEnd = ActiveCell.Offset(20, 5).Address

Worksheets(strSheet).Range(strStart, strEnd).Sort key1:=Worksheets
(strSheet).Range(strStart), _
key2:=Worksheets(strSheet).Range(strEnd)

End Sub