Kner wroteNo I am not using any runtime, neither does the programmer. He just takes the json. files I export and import them in Unity.
Note that Unity doesn't know how to interpret Spine skeletal data in Spine's JSON or binary formats. Your programmer is almost certainly using our spine-unity runtime to load and render the Spine data.
There isn't a way to loop only a part of an animation without writing code to do so, sorry. If you split it into 2 animations, it is easy for the programmer to set the first one and queue the second to be played immediately afterward. The only downside is it may be harder for you to design the animations. You could have one animation that is the full animation (intro + looped part) so you can edit it easily, but uncheck export for that animation. Then you could copy/paste the keys from that animation (or duplicate it) to create the intro and looped animations, which do get exported.
As Erika said, each skeleton is exported as a single JSON file, no matter how many animations it has.