Want to skip a transition basis date field comparison

[SysAdmin]

Hi,

 We have to skip a transition basis two date picker custom fields.

There are two date picker fields Start Time and End Time. If the time selected in these fields is more than 3 hours then the issue should skip the transition and go for an approval else not.

We use a fast track post function in such a case in Jira but how to achieve it with such a comparison is not clear?

Could anyone please help with this?

Regards.