[We don\'t know] \"Masterpage\" for Multisite

Hello,

We want to create a multisite network. Each multisite has as usal its own content. But there should be some content which should be the same for all sites of the multisite network. We would like to create a the main page of the multisite network a masterpage. Its content should be automatically be exported to all multisites so that we don\'t have to update the content on each single multisite.

Do you have any plugin for this task or do you you know another solution if there is no plugin?

Thanks a lot in advance for your answer!