Ted I'd be inclined to contact a seamtress/taylor/tayloress who makes/ alters garments. There's usually such a person in any reasonable size town, Start asking around. That's the sort of person who could easily attach wide elastic loops around a belt which would allow you to place each container in the loop. If each elastic loop is tight enough then it will be held securely.
Shouldn't cost too much and if weddings are going to be part of your portfolio it will pay for itself in no time.I wouldn't worry about how it looks. No-one bothers how the photographer looks at a wedding.
Good idea! Should be easy to make. Just make sure the belt fits so that they can't get pushed out when you sit, kneel, etc.