1) Create a new clean steam account.
2.) You can decide to buy DLCs or not.
3) Register an Account and Download CyberGhost from here (needed to activate region locked game, you can actually skip steppes 3-4-5-6 if you buy GLOBAL version of the game).
4) Install CyberGhost, Run it and Login.
5) In the left corner select as “Simulated Country” Ukraine or Russia.
6) Click the Yellow button to connect.
7) Now start Steam and login with the clean account created on Step 1.
8) Activate the game and download it.
9) Go to “Steam” → “Settings” → “Family” → “Authorize this computer”.
10) Let your Friends (Up to 6 people) to login with the Account and download it (one by one).
11) They need to repeat “Step 9”.
12) Now everybody need to apply SteamSharing fix downloaded before in this way:
12.1) Go to “C:/Program Files(x86)/Steam/common/rocketleague”.
12.2) Copy here the content of the fix and overwrite everything when it asks.
13) Now just login with your own account (not the one created on step 1), you must see it in your Library.
14) You can play all together without problems.
15) Doing this you all going to have an original copy of the game paying it only one copy.