Last saved menu Items take precedence in multisite setup

Issue Summary

Repeatable: Always

Steps to repeat:
1. Download/install Domain Access, Superfish Modules.
2. Share the same Superfish menu block with two different domains with different themes.
3. Create a node for each of 2 domains, neither set to "Send to all affiliates."
4. Save the nodes set each to appear in the same Superfish menu in "Menu Settings".
5. Visit each domain and notice the menus will be the same, according to which had it been saved last.

I have shared content in a single D6 install with a Domain Access multisite setup.

Expected Results:
Normal menu behaviour has base primary links also shared across several sites with custom pages added through Menu Settings of that particular node. The node is not shared with affiliate sites and therefor the menu item does not appear on other sites.

Actual Results:
Superfish Menu links added through admin/build/menu are shared universally as expected. When a node is set to appear in a Superfish menu and saved, it appears on all domains that share that Superfish menu block, even though that specific domain is not allowed node access. Links that were specific to every other domain are then gone, unless one of these nodes is re-saved (in which case, the links that are specific to this domain would now take priority and show on the other sites.)