c# winforms DataGridView and stringArrays.

Question

c# winform
I want to create a stringArray from DataGridView.SelectedCells
Each cell has only one character.
Then: MessageBox1.Show(first four members of the array);
And: MessageBox2.Show(the rest of members).
For example:
If I select 1 2 3 4 5 6 7, MsgBox1 is: 1 2 3 4 and MsgBox2 is: 5 6 7.
If I select 2 3 4 5 6 7 8 9, MsgBox1 is: 2 3 4 5 , and MesBox2 is: 6 7 8 9 .
Any idea about coding, please