Group Exemption Letters are used for Umbrella Organizations so that theirlocal chapters do not have to obtain their own individual 501C3 designation. Idont really see the need if you are just looking at 2 NPOs merging theiroperations. Using the term merger here typically has one of two meanings. 1. A merger where one organization is merged into another surviving organization. Assuming the purposes of the two NPO are similar which I dont think I would understand a merger where they were not then the combined organization would operate under the surviving NPOs exempt status in the future. 2. A consolidation where the two NPOs come together to create a new organization. In this case the new organization needs to create a new legal entity apply for a new tax id number and file a new form 1023. While logistically 2 requires more effort given the politics and challengesof combining NPOs it is not that uncommon.