Hi,
First 2 leave per occasion this can be restricted through config V_T554S through Min and Maximum 001 to 002 days.
Leave has to deduct from another quotas as said by sikindar you can do it.
Below BADI will restrict employee not take leave more than 3 times a year.
If you are using ESS/MSS use badi :- PT_ABS_REQ
For R/3 you can use BADI HRPAD00INFTY
Regards,
Raja Sekhar