Work around for using OR in Joins

[MIS]

I want to use OR in the join expression, but it seems only AND is supported
as of now.
I have a work around though to use DeMorgan's law {C1 OR C2 = !(!C1 AND
!C2))} , but it would be nice if somebody can point me to the location in
code base that would need modification to support the OR in the join
expression.

Thanks,
MIS.