Custom Magento module to update Active Campaign email database

I have a Magento website which is connected to the Active Campaign (AC) on site edition ([login to view URL]) email software. Active Campaign have their own Magento module to connect with AC: [login to view URL] This works fine, but I need to add some extra functionality via additional API integration. Their API is detailed here: [login to view URL] Basically I need: An additional module that leaves the Active Campaign module in place (in case of updates) When a customer makes a purchase, if they are not already subscribed, they are added to the AC email list There are 2 stores on the Magento installation. A custom field in the AC list needs to be updated depending on which store the purchase comes from. i.e. the custom fields are "Purchased from store 1" and "Purchased from store 2"; when they buy from a store the corresponding custom field should be updated to "Yes" If they are already subscribed to the AC list their a new entry is not added, but the custom field detailed above are updated. The API has "subscriber_add" and "list_field_edit" which should work for these options, so for a programmer with knowledge of Magento and API calls this should be fairly straightforward.