I have multiple OG groups where a person posts within the group and the group is private. I need to have a field on each node that shows the serial/count/id of that node within its group.
nid=1 & post_id=1
nid=2 & post_id=2
nid=4 & post_id=3 --node 3 was created in group B, but post_id is only for group A.
nid=3 & post_id=1 -- This is the 3rd node created on the site but the first in group B.
How do I display/create a value like post_id in a node template file? Can this be done through Rules when creating a node, or calculated on the fly within the template file?