Region info is very important. I can't play as raiders with friends on Russian version and EU version if mine is US version. They can be matched as antag, though.
First and foremost , from which region are you coming from . Mine for example is the EU . Secondly (this is optional) , do you have mics ? Feel free to respond by adding my nametag blazeman-18- if at least the first request from above is manageable .
If you make a PSN account and select it to be of their region, EU for example, then you can download the proper client.
I am NA but I have an EU account that I used to download the EU version of Spacelords to play with other EU people.
Simply make the account with the corresponding region, go to the store and download the client. You DO NOT have to use your new account to play on that client. Once it is downloaded you can access it from your main account.
There is really no way to tell different Spacelords clients apart, though, so I just use my trophy percentage. Your PS4 will automatically load the correct client, if you have it, when you accept an invitation from whichever region.
So, if you get an invite from a player using the NA client but you have both NA and EU clients it will choose the NA one for you. Pretty cool, actually.