An offline grouping proof shows that multiple Radio Frequency Identification tags are scanned simultaneously, regardless of a reader device's network connectivity. However, the previous offline grouping proof schemes are unsuitable for passive tags, and do not handle errors that cause performance degradation, such as transmission loss or synchronization failure of shared values between tags and a back-end database. In this paper, we propose an efficient offline grouping proof scheme using multiple types of tags. It makes use of an agent tag which does computing operations instead of the passive tags to reduce the computational cost of them, thus it eventually shortens the time for generating a grouping proof. We show that the number of modules and operations of the passive tags in our scheme are less than half of the previous schemes while it achieves the enhanced security and scalability.