Garter toss/Bouquet Toss

We really want to do the garter toss/bouquet toss but we were talking about it and we have like no unmarried people coming to the wedding. Almost everyone is either married or engaged. I have been to weddings where it came time for this and no one stood up and it was really awkward.
So my question is --does anyone have any ideas on what we can to thats similar that doesnt involve single people. I heard of the anniversary thing but unfortunately I feel like this would upset my grandmother since we just lost my grandfather recently.
Thanks for your help!

If it's something you really want to do, why not just ask everyone to come up?

Also, I'm so sorry for the loss of your grandpa. I lost mine 2.5 years ago, so I totally understand where you're coming from. But, with your anniversary idea, remember that your wedding is in June, so your grandma will have some time between now and then, so things won't be so fresh. Maybe she would be fine with it? You could always try talking to her about it.