Why yes there is… it’s explained in the documentation quite well.
https://plugins.twinpictures.de/plugins/collapse-o-matic/documentation/
`Rel Attribute Highlander Grouping
If -highlander is added to all members of a group, then expanding one member will collapse all other members of the same group. Members of other groups will not be affected. Highlander: There can be only one.
[expand title=”Monkeys” rel=”animal-highlander”]Target Content[/expand]
[expand title=”Donkeys” rel=”animal-highlander”]Target Content[/expand]’
So you place the tag rel=”xxxxx-highlander” to all “Expand” tags on the page.