It's hard to tell exactly from the info given to us, but generally you'd use the Section Expert, click the X-2 button beside the Suppress property for the appropriate section, and enter a boolean formula that describes when the section ought to be suppressed.
For example, if Group Footer 2 is the section to be suppressed if the field is equal to "C", then you'd enter
{YourTable.WhateverField} = "C"
in the X-2 button beside the Suppress property for Group Footer 2.
Please try to include more info in your posts so that we're not working in the dark.
Bob Suruncle