Yes – use Bring a tree into this one. You can bring it in quickly and sort out anyone who's there twice afterwards, or carefully, person by person, so you check everyone before they join. For example, your tree and your cousin's tree of the other side of the family can become one.
Where to find it
Settings (bottom row of the top bar, far right) → People builder → Bring a tree into this one
Only people with the "Add people" and "Undo saves and restore" ticks.
On a phone: if the Settings tabs are tucked away, press ☰ Menu (top left) first.
Still stuck? Talk to a real person: send us a message, or email support@mywholefamilytree.com