If you double click on the For Loop Container of SSIS, a new window will open where you can set up the condition based on which the loop will continue. There is a field called EvalExpression where you can set an expression and if this expression holds true, the loop will continue. I was just wondering if it is possible to introduce an logical OR condition in that field. Just you have already thought, it takes pipes (||) to implement OR between two conditions. Hopefully, the below snapshot will be enough if you have any doubts:
Zahid's blog on Data Engineering and BI 
I solved this by using an Expression Task at the end of the flow in my For Loop Container to set the value of the package variable I use in the EvalExpression.