With a single license, multiple instances of Composer can be run on the same PC at the same time. As a result, more than one experience can be edited at the same time and content can be copy and pasted between them.
Due to advanced capabilities like binding and remote actions, the algorithms used by Intuiface to paste copied items can be quite complex. Luckily, all of this happens under the covers so it should all work seamlessly. For example, if your scene references an interface asset, the copy/paste of that scene will also copy over the interface asset as well even though, technically, the interface asset is independent of the copied scene.
It is not directly possible to copy multiple scenes - or an experience as a whole - and paste those scenes into another experience. Only one scene can be copy/pasted at a time. However, there is a workaround.
If scenes are grouped within a sequence, the sequence can be copied from one experience and pasted into another, bringing along all scenes located within the sequence.
In the highlighted area of the image below is a sequence comprised of three scenes:
Thus to copy multiple scenes - and/or to avoid the limitation identified below - create a sequence in the source experience and move all scenes to be copied into that sequence. Copy that sequence and paste it into the destination experience. Once pasted, you can delete the sequence in both the source and destination experiences.
The only known copy/paste limitation between two or more instances of Composer concerns triggers and actions. Triggers and/or actions cannot be copied and pasted independent of the item (e.g. asset or collection) with which they are associated.
This means if a trigger is in Scene A and the action target is in some other scene, the trigger/action pair won't be pasted if the tigger scene is copy/pasted first.
NOTE: The workaround based on the use of sequences, mentioned above, will avoid this limitation.