Subject-to - seller paying the 2nd mortgage - what should contract look like?

[Nick L.]

Hi. I am working with a seller on a subject-to deal. Here is the info:

Owes 47k on first (payments = 387/mo PITI)
Owes 7k on second (payments = 90/mo PITI)

The seller has agreed to continue making the payments on the second mortgage.

How do you suggest I write up the agreement with this seller? Should all of the above terms and conditions be solely written in the purchase and sales agreement? Or should there be an additional contract/addendum regarding the seller paying back the 2nd mortgage?

The exit strategy is to assign this contract to a landlord who wants the property as a rental. I want the end buyer (landlord) to be comfortable with the agreement.

Thanks