There are two ways to filter a user feed. The most efficient may be to use a “search” feed though you will initially be limited to tweets made within the last 7 days. Once a tweet is retrieved it will be saved indefinitely, however.
Using a “Search” feed
Our guide to using search feeds can be very helpful for complex searches. To filter a user account feed by a hashtag, use this example:
[custom-twitter-feeds search="from:account #hashtag"]
[custom-twitter-feeds search="from:account #hashtag #anotherhashtag"]
To create a feed that only uses specific screen names but also only shows tweets that include a specific hashtag, you can use the Moderation section on the Customize tab
You can also use the “includewords” setting directly in the shortcode like this: