Option Group to Text Field

[Stengah]

I'm trying to use an option group to generate a prefix into a Text field. So far I have generated variables and the If statement I think I need to get the prefix I need. This is where I'm drawing a blank on how to incorporate it into the rest of the text.

Any help would be greatly appreciated.

Code for variables & If Statement:

Dim normal As String
Dim service As String
Dim export As String
If Option12.Enabled = True Then
normal = " "
ElseIf Option14.Enabled = True Then
service = "S"
ElseIf Option16.Enabled = True Then
export = "EX"
End If