You might want to post this as a product enhancement request in Ideas for Jive. I've heard others mention this in older threads. There doesn't appear to be any workaround at this time.
Love Jill's idea of posting as a product innovation idea, and I know similar asks to this have come up before, so very valid for product to hear. With that said, there are some great work arounds if interested. I noticed that your team is now on cloud (which is wonderful)! As you may know, more and more external users are leveraging tiles over widgets now. They are more responsive and in many cases provide a way to curate content activity a bit better. Widgets would allow this too though, if you wanted to stick with those... such as showing popular/trending content over just recent activity. Maybe a blend of the two, where featured content and other items are the main focus with recent activity flowing below. There are any number of strategic ways to do this, with tiles or widgets. Here are a few options I personally like related to group layouts. Doing a similar thing for the landing page itself is a bit of a different topic, but still keeps the same ideas in mind:
The beauty of tile based groups, like in that second and 3rd link, are that they allow for our "Pages" feature to allocate more than a single landing page per group. This affords more organization without having to put everything on the landing page, or sub-group models without needing the sub-group.