You can try do so by setting up collection fields for each tag, add value in the items that should contain the tag. Then create a query that will use a isEmpty() to see if there are any items matching the value. This will return the items that do not have any value in the specified field and therefore should be collapsed.
You can find more information here:
https://www.wix.com/corvid/reference/wix-data.html#query
https://www.wix.com/corvid/reference/wix-data.WixDataQuery.html#isEmpty
https://www.wix.com/corvid/reference/$w.Repeater.html#forItems
https://www.wix.com/corvid/reference/$w.Repeater.html#collapse