Restrict theme association across workspaces with shared users

We have two distinct products with unique roadmaps and customers and each in their own workspace. However, there are shared users between these two products. When one of these shared users is working with an Idea in product #1 in the Idea Panel, I would want the list of themes to select from to be restricted to only the themes created in product #1 workspace. However, what I’m seeing in the available theme list are themes from both product #1 and #2 (albeit the list is grouped by product #.

As the list of themes across both products is long, the superset is very long, risking that users will not find the right tag for the right product easily, or just stop adopting theme tagging.

I would like to isolate the list of available themes between workspaces if a user has access to multiple workspaces