Jira behavior to restrict field edit when sprint is active

[KRC]

I want to restrict all users except U1 U2 & U3 from editing a field, let's call it as  Field 1 only on issues when the sprint is active and in the non-active sprint days all users can edit field 1.

I can achieve a part of this by using behaviors by making field 1 read only by adding the condition - "Except-when behavior will not happen when the current user is U1 or U2 or U3" 

[Divya Suseelan]

One option is to remove the field from the Edit Screen and use it in a transition where you can write conditions to restrict specific users to allow the transition.