I've been using this invaluable night sky tool to help make sure I don't put the moon of my planet in the wrong place given a time of day and so I get the phase right.

I'm wondering two things:

1. Is there a tool like this that would let me add in a fictional celestial body (such as another moon) to keep track of? If none exists, as I suspect, where can I find the math to explore to calculate all that?
2. Failing that, so I can keep using that tool, is there any way a second moon would appear to hang out near the closer one in the sky? For example always appearing either ahead of or behind throughout the year, or even alternating between those two. I don't think trojan moons would work for this, but I obviously have no idea.

Ultimately I am biased toward using the night sky tool above as I fairly need something to visualize it, not just calculate it, though I could possibly try programming something suitable for my purposes if I knew the math. I have been told that the math for even one orbit is incredibly complicated, though, so I don't have much hope for that.

It's still early days so it's not the end of the world (literally) if there isn't a second moon, this is more of a curiosity than anything. Thanks.

Is there any way a second moon would appear to hang out near the closer one in the sky? For example always appearing either ahead of or behind throughout the year, or even alternating between those two. I don't think trojan moons would work for this, but I obviously have no idea.

It's still early days so it's not the end of the world (literally) if there isn't a second moon, this is more of a curiosity than anything. Thanks.