So, it wouldn’t start initially, but would then start after some time? You may be able to accomplish what you want with triggers, especially considering that triggers can be action items that run queries, so you could do something like have a table in the database that had a column for “active” and a column for “groupid”, and then have the various groups consult that table for whether or not they should run.
As for disabling an item- you can’t do it on the fly, but if you were to stop the group and make the item “read-only” it would be essentially disabling it, to the database. It would still be active on the OPC side- read only mode is normally used to allow an item to be referenced in action items, the trigger, the where clause, etc. without being stored to the DB.
Hope this helps,