Housewarming Party/Pregnancy Announcement Ideas?

If all goes well at our ultrasound next weekend, my husband and I would like to announce our pregnancy to our parents and grandparents at our housewarming party in a couple weeks. I don’t want to do a big group announcement because there will be friends there I don’t want to announce to quite yet, so I’m planning to do individual “announcements” more quietly. My idea is to bring each person upstairs on a “tour” of our new house, take them in the room that’ll be a nursery, and tell them there.

My struggle is figuring how how to do the actual “tell.” Should I make a sign and hide it in the closet? Should I have a digital test sitting on a shelf? Should I make a onesie and hang it somewhere or put it in a gift bag and give it to each person? Does anyone have any better ideas?

This is the first grandchild on both sides, so I want to make it special. Any ideas would be appreciated!