Splitting an php array into teams

I have an array with a random amount of elements (it's a online game * random amount of users each time). I want to split this array into two teams, how is this achievable?

Example of an Array i have where 4 & 3 are ID's of users.

Array ( [0] => 4 [1] => 3 )

I haven't found so much information on this, and the information i have found is pretty hard for me to understand, so i would deeply appreciate some sort of explanation on how i can do this.

If i have not provided enough information, just let me know! Thank you for taking your time reading my question!