Validation on Original Estimates

Hi,

I have created one "Internal Targets" projects and created Tasks like Casual Leave, Privilege Leave, Sick Leave etc. under it. Now each employee has a fixed no. of hours against different leaves which is set at the beginning of the year. I want to put validation that no employee can take leave more than the hours which is set as "original Estimate" against him. Like in below case Fig-1, I don't want to allow Emp#1 to book time more that 85 hours for CL. I can see at present it is allowing. Please advise is there any way to validate that through Time Tracker.