Just follow these steps:
1. Go to plan view and create a blank page wherever you like.
2. Name this page according to the target, you want to link to (optional).
3. Rightclick the icon of this new page and choose "Menu Options/Include Page without Hyperlink".
4. Go to your site menu and localize the entry of this particular page.
5. Select this entry, go to the command strip on top of the Muse window and enter the address of the homepage you want to link to into the "Hyperlinks" field.