It won't be possible to make 24 man groups for CT, it's just ridiculous why such a feature isn't given high priority for this patch.
But at least try to give us an option to find groups on your own server only, that shouldn't be too hard to implement, because SE has grouped servers already for DF.

This way, it will be possible to try to make a 24 man premade for CT, by queuing up at the same time.