With Facebook Poster you can post to Facebook Fan pages and as like Group posting you are too allowed to post in Facebook Fan Pages. Posting to Fan pages is same as posting to Facebook Groups.
To post on the Facebook pages, follow the steps as shown :
Importing Facebook Fan Pages into Facebook Poster
First, you need to add your Facebook accounts in the Facebook Poster and once you have added the Facebook Account, your all the Facebook Fan pages will be loaded.
After adding the Account go to Home Page.
Note: Make sure the Page button is Enabled as shown in the below screenshot.
If you enable Groups and Pages then it will show you both the groups and pages but if you enable only the pages option then only the pages will be shown.
Now after enabling the pages option to compose your message and choose the pages you want.
Now schedule or Post instantly to the Pages.