Flexibility with Tracking Details - always require a work item / always ask for tracking details

Right now, we have set mandatory work item/comment for all activity types.

Our team would like the ability to make it mandatory to enter a work item when only SOME activity types are selected. We would like the flexibility / ability to NOT make it mandatory to add a work item to some activity types and make it mandatory on others. 

We need it especially for backlog activity types for the collaborators to have entered a work item whenever they input their time, but we would also like the ability to leave work items out for internal items like PTO, vacation time, parental leave, sick days, etc. 

With current functionality, I can only set it across the board within Timetracker's "Rules" to make a work item or activity type mandatory, when our team needs the flexibility to only make certain work items and activity types mandatory.

Is there a way to add it to your backlog and make this in future iterations?