How can set the fixed dates as a multiple dates list in timer condition?

Hello,

I am developing a kind of scheduler process.

Manager created multiple tasks which have a due date. Whenever the due date reaches I would like to send a notification to the user and manager at the same time.

I returned the due dates into a process variable as an object, however, in the timer condition, only allowed java.util.Date type.

is it possible to set the fixed dates as multiple dates in the groovy script?

In the case of my process, how to approach the solution?

I am sorry the question is vague.

Any helps would be appreciated.

Thanks in advanced.