Is there a better way?

[Sascha_Billian]

Since you already have a group, you can enumerate all items from a rule.
See

Enumerating all Items from a rule?

Hello, First time here to forgive me if I’m posting to the wrong part of the forum. I wonder if there is a way to enumerate all defined Items from a rule? Instead of addressing each item manually i.e. Item1.state == ON etc it would be nice to do a for each over all items and check the state of each. Thank you for any assistance. Br, Freddy

Inside your rule you then can check the current items state vs. the previous state (persistance needed) and then update the item.

I think the best way to educate yourself is actually to do something with your OpenHab. Learn from examples/solutions in the forums, try different things out and so on.
No need to be a JAVA expert in my opinion.