You can advertise all of them separately as /26 or summarize them as a /24. Configuring a network statement for the class C will automatically cause the router to advertise them as /26 routes.
If you want to summarize them, you will need to configure "ip summary-address eigrp" on the interfaces where you want summarization to take place.
Hope this helps,
Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
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