GTA-V, Online PS3 and PS4 [duplicate]

I have PS4 and GTA-V, my friend has the GTA-V too, but he have PS3. I have PSNPlus, but my friend not yet. The reason he don't have it, is because we want to try to play GTA-V online, but togheter.

My question is:

When he buy PSN-Plus, we will be able to play togheter online? I ask it because we have different PlayStations..

Unfortunately, online play between PS3 and PS4 isn't possible in GTA V.

Though PS3/4 cross play is apparently technically possible, most developers choose not to, probably due to the difficulties in maintaining balance between different versions of the game.

That aside, I imagine that crossplay in GTAV would be almost impossible to work out due to the differences in the maximum number of players between the two versions (30 in current, 16 in last gen, I believe).