I am trying to add a chatter component to a VF page, but am having some difficulties.  I have been able to successfully create a vf page that displays a Chatter Group feed, using the following:

<apex:page standardController="MyCustomObject__c" sidebar="false" showheader="false" >
  <Chatter:feed entityID="{!MyCustomObject__c.Group_ID__c}" / >
  </apex:page>

I would also like to render the follow/unfollow (join/leave) button for the group.  According to Salesforce's documentation, there is a <chatter:follow> component which should do this.  If I follow the same logic as my previous example (if group feed is simply a record feed, then group join would logically be the same as record follow).  When I try the following I am unable to get the button to render:

<apex:page standardController="MyCustomObject__c" sidebar="false" showheader="false" >
  <Chatter:follow entityID="{!MyCustomObject__c.Group_ID__c}" / >
  </apex:page>

However, if I replace "{!MyCustomObject__c.Group_ID__c}" with the ID of a users profile or record, the follow button appears.  So it seems that groups are only like records when it comes to feeds, not following or joinging.

Does anyone know how I can add the Join/Leave button for a Chatter Group (public) on a VF page, as I was able to add the group feed? 

One other option I was considering was to embed the Chatter Group Profile Page on the VF page, however this VF page is going to be included on the page layout of one of our custom objects.  When I try this, it includes the standard Salesforce header and top navigation in the iframe.  It also includes the left column of the group page which includes the group image and description and becomes quite busy.  Here is the coded I used

<apex:page standardController="MyCustomObject__c" showheader="false">
  <apex:iframe src="https://cs14.salesforce.com/_ui/core/chatter/groups/GroupProfilePage?g="{!MyCustomObject__c.Group_ID__c}" scrolling="true" id="theIframe"/>
     </apex:page>

I was able to remove the standard Salesforce header and top navigation by adding $isdtp-vw to the URL.  Here is the code: 

<apex:page standardController="MyCustomObject__c" showheader="false">
  <apex:iframe src="https://cs14.salesforce.com/_ui/core/chatter/groups/GroupProfilePage?g="{!MyCustomObject__c.Group_ID__c}&isdtp=vw" scrolling="true" id="theIframe"/>
     </apex:page>

Unfortunately, it seems that the isdtp UNSUPPORTED by Salesforce. I also have not been able to get the EntityID reference ({!MyCustomObject__c.Group_ID__C}) in the URL to pick up the ID from the record the VF page is displayed on.  It works if I have the exact ID included in the URL (not ideal, but workable in this situation)

I would really like a VF page that:

• 1st choice: a VF page that inlcudes the group feed (including the bar where you can post/file/link/poll/share, as well as the button to join or leave the group.  (so basically the center column of the standard group profile page, plus the join/leave button, without the standard salesforce header)
• 2nd choice: If neccessary, it would be acceptable to include the right column of the standard group profile page, which includes the join/leave button, members list and group files list. 
• last choice: would be to include the entire group profile page, without the standard salesforce headers through a supported method.

This VF page would be added to the page layout of a custom object.  This custom object would have a field that would contain the ID of the group that should be displayed/reference in the VF page.  I would prefer the reference the Group ID on the custom object, versus having to have multiple VF pages for each group.

Any insights would be greatly appreciated

Michele