You need to distinct those specific nodes using taxonomy or a custom field, like a boolean field, say, 0
means no vote and 1
means needs voting. Then use the the flag module to filter those nodes. like this
UPDATE :
The basic idea is, when user flags
a content, you can set all of the 1
s to 0
in this way no more content will be votable. To do so you need to use hook_flag_flag function. in this function use node_load to load the nodes of boolean value 1
, set it to 0
then use node_save to save the node.