I have a preschool app that includes a Child Registration Form and Attendance Register. The Register includes a look up field of the children's names to be selected from. I want to hide the names of the children who have left the service from this look up field (whilst keeping the original records).

I added a radio button with 2016/17 and 2017/18 options so it is possible to filter the records but this doesn't hide the names in the look up field.

How can I only include current pupils in the look up field and hide past pupils?

Thanks

Gill