idk i got same problem

The merge mechanic starts when chase is active and also when they are idle (but that's rare).

From there on it's random (also influenced by the % for how likely they are to connect which is an option that you can modify in settings)

But in future I'll most likely add a new entity alongside the singular rust virus so that you can automatically spawn in an already merged one.

Can you simply put a "Roped Rust Virus" in the spawning? Or add a command to increase rope chance