How to group similar column titles together????

I have an excel spread*** with 6 column titles as follows:
1st column title = ob1
2nd column title = ob2
3rd column title = ab1
4th column title = ob3
5th column title = ab2
6th column title = ob4

I have about 200 lines of information on each column. I want to run a macro
/ function on this spread*** and my spread*** should regroup similar
titles together as follows:

1st column title = ob1
2nd column title = ob2
3rd column title = ob3
4th column title = ob4
<blank column>
5th column title = ab1
6th column title = ab2

Can someone think of any way to do this? (A macro solution would be
preferable)

P.S. I have about 16 column titles that I need to group in my excel file.
For simplicity sake, I have explained my problem with 6 columns.
.