diff --git a/29.md b/29.md
index 2496989d..0c279ad4 100644
--- a/29.md
+++ b/29.md
@@ -50,6 +50,8 @@ The weekly hash MUST happen in the client and in the relay in the exact same way
 4. For each group, create an array of event ids: [id1, id2, id3], JSON-serialize it and hash it using SHA-256
 5. Return a list of the formatted `.created_at` and the hashes. 
 
+Clients must keep records of which events are coming from which relays to sucessfully filter only events from that relay and compare hashes.
+
 ### Why weekly? 
 
 Simplicity. We could do a recursive approach where the Client chooses the format (e.g: `YYYY`, `YYYY-ww`, `YYYY-MM`, `YYYY-MM-dd`, `YYYY-MM-ddHH`, `YYYY-MM-ddHHmm`). This flexibility allows for some cost savings but adds complexity to the implementation of this NIP.