These two devices can’t talk directly to each other because they use different protocols. The GE device is Z wave and the Osram device is zigbee.
But they can both talk to the SmartThings hub, which is one of SmartThings big advantages. So you could have the Osram switch send a message to the hub which then sends a message to the GE switch to turn on the lights.
Having said that… The Osram device itself will require custom code to work with SmartThings. There’s no way around that right now. That’s going to be true of pretty much every zigbee device which is not on the official “works with SmartThings” compatibility list.
The good news is that most certified Z wave devices can work as a generic on/off/dim switch with SmartThings without requiring any custom code, whether they’re on the official list or not.
And you can use the official SmartLighting feature to have one switch “follow” another, which would solve the use case you described.
And there is a Z wave battery operated switch which is very similar to the Osram.
So if you’re willing to use the gocontrol device, you could make it work without using custom code.
https://www.amazon.com/GoControl-WA00Z-1-Z-Wave-Scene-Controller-Switch/dp/B01BKWG9XS/
Custom code sounds confusing at first, but really it just means that you are going to copy the author’s code and paste it into your own account. It’s pretty straightforward. And if you are willing to use it, it will open up a whole additional set of features and devices.
The following thread explains the basic custom code concept. You might take a look at it and see if it’s something you would be willing to consider. If not, that’s fine, you should still be able to do most things, but as in this example it may mean choosing a different device than you were originally looking at.