Auto Increment Level in Weekly Subscription

Hi,
I was looking for limiting recurrence and found out the answer in first reply of http://www.s2member.com/forums/topic/limiting-membership/ by Cristián – Thanks for that.

Moving forward my customer wants to auto increment level access with the weekly payments. It is going to accept 3 weeks payments in 3 installments (weekly). Here it is required that with 1st payment the subscriber gets level 1 access, when the auto recurring installment is received the subscriber should automatically get the level 2 access and finally with the final installment the user gets the level 3 access.

Can you tell me how do one achieve giving higher level access with each installment under the same subscription?

Thanks in advance!