As has been pointed out by @Michelle_IOM in another post it is already possible for donor and recipients to cross reference each other and the IATI Standard does already make provision for that to happen. However, as @Herman had mentioned (and it was also my understanding) I think that the original intention for traceability within IATI was just to trace upwards within the funding chain? Both @Herman and @YohannaLoucheur have pointed out that a donor or funder can generally provide their own originating IATI activity identifier to the recipient via contract documentation and/ or as part of the contract management business process etc .
Interestingly, some of our most recent work within the Grand Bargain (particularly around issues relating to Localisation) is highlighting that there would indeed be value in being to be able to trace both ‘up’ and ‘down’ the funding chain. Presumably for this it happen, Donors and other funders would need to regularly ‘harvest’ the recipient activity identifiers and add them into their own systems. I think this process could certainly be automated and it would also provide donors with an automatic confirmation or validation that recipients have also now published the receipt of that funding to IATI? As a result I would be very interested to hear any views from donors or others on the practicalities and appetite (or lack of?) for making this happen?