I don’t know if I’m blind or if this feature just doesn’t exist, if it does please tell me how to use it.
So when you add an stl with multiple models, you get the option to split this model in to objects or parts. But there is no way to add multiple objects to one group. Which is very handy when using a mix of print order, like you want to print 5 objects in one color and a sixth with its own color. If you set them all up to print by object they wont fit the build plate, but if you print the first 5 together and only the sixth with its own color alone they would fit and print a lot faster.