Mass text with RV50X

Hi, our hospital is using text messages to alert doctors to critical hospital situations (mass casualty events, etc). The RV50X works well for individual SMS but does not seem to handle mass messages. Even 120 SMS messages seem to ‘get lost’ in the modem. We use PageGate by Notepage, Inc. as the app. Is the RV50X the appropriate modem for this purpose? Thanks, any help appreciated.