I'm trying to make a kind of drop list sub navigation scheme using tags in posts for specific categories.
So, I have various pages that list posts from a certain category. On each category listing page, I'd like to show a drop list of TAGS from the posts ONLY in the current category.
NOTE: the drop list is necessary since these tags may add up in categories that have numerous posts listed. Simply showing a block or "cloud" of linked text could get too long and cluttered to display cleanly.
EXAMPLE CATEGORY PAGE
As seen in the link above, I have a Wine & Dine category listing page that shows all merchants relevant to only that category.
In the post for A'Romas I have a tag entered Coffee and Tea. Likewise, Cellars of Sonoma has the tag Wine Bar and so on. These tags then are simply refinements or keywords belonging to the parent category of Wine & Dine.
To utilize this drop list navigation scheme from post tags in a specific category, I need two things to happen:
1) DROP LIST OF TAGS
A drop list is shown at the top of the list of Wine & Dine category merchants with the tags found within those matching category posts (such as Coffee and Tea, Wine Bar, etc.). When one of these tags is selected from the drop list, a listing page is shown with just the posts that match that tag within Wine & Dine category.
Example: once at the Wine & Dine category page, selecting Coffee and Tea from the drop list only shows A'Romas (since there's only one coffee and tea shop listed). Selecting Wine Bar from the drop list would show both Cellars of Sonoma and Wine Spectrum Shop+Bar (since both share the selected Wine Bar tag).
2) PERSISTENT DISPLAY TAGS
Once a tag listing page is shown, the other tags in the drop menu for the Wine & Dine category are still available. This way, when a person selects the Coffee and Tea tag from the drop list, they can still move on to other tags in the drop list such as Wine Bar without first going back to the complete Wine & Dine category listing page.
In other words, the tags drop list is a sub navigation for refining the views of all posts within the Wine & Dine category.
WHAT I'VE TRIED
I've found a lot of info about how to display posts with certain tags, but it's not as a drop list that is preserved as a link menu for a category.
I also looked at using Custom Fields, but that seems like a complex alternative to tags which is a perfectly good method. Also, I couldn't find any info about how to turn Custom Fields into a drop list as described above.
Thanks for any help!