I don't know if I understand you correct. Sorry if isn't what you want.
If you want the first sprite of several instances of this sprite, I would use the IID not the UID. The IID is a number in ascending order number starts with 0 for the first sprite.
You can then easily access a sprite with a definite number with the condition 'pick nth instance'.
For example the first sprite with IID=0:
System| Pick Sprite instance 0