Delete a Terminal Field

Hello, I have two form buttons with the same name. Depending on their relative positions, I want to delete one of the fields. I am using this:

var f1 = this.getField(fname+".1");
if (f1 !== null) {    this.removeField(fname+."1");
}

where fname is the field name. However, the terminal field is not deleted. Is there a way to delete a terminal field with Acrobat JavaScript? Thanks.

Rick