Does this exist? because I saw an alliance able to make combined assault mostly with 4-5 members at once composing 70 squads atleast.

If the question you are asking is can one then one person from an alliance send an attack off as a group yes. If each person in your alliance has 20 ships and its a ten man alliance you can send an attack of 200 ships to someones colony or an outpost.

when ur alliance members, including u, sending squads from the same OP, to the same destination, with the same ETA together, they will become a joint group of squads.

However even though they are attacking as a group one individual player can turn their squads and the others will still continue towards the target.

Oh, this clears everything thanks