That's not what XDEF/XREF are used for (EQUs&co).
You could see EQU/SET/RSSET/.. as "compile time" variables/constants. Now, if you would do something like:
Code:
QQQ EQU 123
varQQQ: DC.L QQQ
then you would use XDEF/XREF with varQQQ. To handle QQQ you simply include a header file (if they are in a separate file) and don't involve XREF/XDEF at all.