Firefox - Múltiples Home Page

Home Page

Here you are able to specify the page (or tab group) that Firefox will show when you press the Home button. Enter the address in the Location(s) field.

Click Use Current Page(s) to use the page you're currently visiting. You can also use multiple home pages. If more than one browser tab is currently opened, this button will set the whole tab group as a start page.

To specify the home page(s) using a bookmark, click Use Bookmark.... You can even select a whole bookmark folder to be used!

If you want to restore the default home page, click Restore to Default.

(Vía Firefox Help)