group inline-content?

hi,
i’d like to know if it is possible to group inline-content boxes together as if they were a gallery?

i tried to use the rel-tag for it, but that didn’t work: the first box opened shows the button to go to the next, but clicking on it creates an empty box, even without the button to close it or anything.

is there any possibility to get around this problem?

any help is really appreciated, thanks a lot already in advance,
a.beck

https://wordpress.org/plugins/easy-fancybox/