There's really no such thing as "linking" itineraries.
​​​​​​Since your first flight is on Garuda, it's a matter of Garuda policy and the agent's discretion. Garuda certainly *can* check the bag through, but that doesn't mean it will.
Garuda questions are best addressed in the Other Asian Airlines board.

You didn't ask, but two hours between separate tickets is pretty risky, regardless of baggage.