>>Tim,
>>
>>You can use ProjectHook BeforeBuild Event to do any checks and even cancel build by issuing NODEFAULT. Another way to prevent the problem is to use a heder file with something like

#DEFINE SUBSTR SUBSTRC

>
>Won't that cause the people who use SUBSTRC to throw an error trying to compile SUBSTRCC ?

No, it replaces words/tokens not substrings.