Suppress section formula

Hello, I'm trying to suppress the page footer of a report if {table.species} in the details section does not equal "SHEEP". The problem I am having is that I only want it suppressed if NONE of the records equals "SHEEP." Here is my current formula (Basic Syntax):
If {InvD.Species}="SHEEP" Then
   formula = false
Else
   formula = true
End If

If ANY of the records contains something other than "SHEEP", the section is suppressed. I only want it suppressed if "SHEEP" is nowhere to be found. There must be a simple operator or something that I'm not finding. Thanks for the help.

At the detail level have the following formula.

shared booleanvar suppress;
if {InvD.Species}<>"SHEEP" Then
suppress = True

In the the page footer suppress formula, put
shared booleanvar suppress;
suppress

Now if their are multiple pages to the report, then you will need another formula in the page header
shared booleanvar suppress := False;

You don't have to booleanvar, but it is simplest data type to use.