Thank you for your post.
In the future, please post to the "Using FileMaker Pro" board as this board is reporting issues with our products.
With that said, assuming your fields are Start Time and End Time, you could create a script that checks the current time [ Get (CurrentTime) ] with the values in the two fields and then display those records.
If the shift is one field, then you'll still have to do some comparisons.
What you have tried? This will give me a better understanding why it isn't working the way you expect.