[FUNExtreme]

I think that would be possible by removing every gang that is higher than the removed id, then setting the AUTO INCREMENTATION id to the removed id and then readding the gangs you removed.
Example:
- Gang ID 1
- Gang ID 2
- Gang ID 3
- Gang ID 4

id 2 gets removed

- Gang ID 1
- Gang ID 3
- Gang ID 4

Delete everything after the removed gang

- GANG ID 1

Set the AUTO INCREMENTATION to 2
Readd the Gangs

- Gang ID 1
- Gang ID 2 (Was 3)
- Gang ID 3 (Was 4)

Like I said, it is possible. I could show you how to set the AUTO INCREMENTATION value but I really suggest you to leave it as it is. In my opinion it is not worth the effort!