There are way to spawn single object after research (spawnedItem), however is it possible to add an option, wich allows to spawn multiple items, soldiers or even crafts after research, like mentioned above spawnedItem, that will use not single object ID, but list of objects as arguments.
For example:
- name: STR_RESEARCH_NAME
spawnedItemList:
- ItemName1
- ItemName2: N
- SoldierType: N
- CraftName