The paper proposes a new notification rule for mobile instant messengers called "Ten-Minute Silence" that aims to reduce excessive notifications. A field trial was conducted comparing the new rule to existing messengers. It was found that tying consecutive messages within 10 minutes into a single notification session impacted the messaging experience across different conversation phases by encouraging more thoughtful starting and easier ending of conversations. The refined notification design also allowed for improved accessibility to past conversations. However, further exploration is needed to understand impacts on different group sizes and communication contexts.