IT0169 and delimit the records

Hi Experts,

I have 4 plans A,B,C,D (subtype) under IT 0169 (Savings plans)

My requirement is:

IF i have a record for subtype A and I want to create a new record for subtype B than Subtype A should be delimited with end date = start date of subtype B and vis-a-versa.

Pls let me know how to achive this scenario.

Regards

Sachin