Can I introduce a new gerbil to my two other gerbils?

[Sydney]

I have two male gerbils that are about the same age. They are a little younger then one year and they have been in the same cage for about 6 months. They are great friends but I was wondering if I could introduce a young gerbil to them. I read on a website older male gerbils would take a younger gerbils as it's baby. The size of the cage isn't a problem because we have a 90 gallon tank and we just added a regular sized bin to it. Would my two gerbils be okay with having another gerbil or should I just leave them the way the are? Thanks.
The younger one would be a male and I have a cage set up for the split cage method.

 

[Tyrell]

I definitely think you should get another gerbil. One reason is just in case one of your gerbils die's suddenly, your other gerbil will still have a cage mate and he won't be upset. Also, the gerbils will love the extra company.
Sometimes it usually doesn't always work out when you try to add another pet to the cage. It really depends on how you introduce them. If you introduce them all correctly, I'm sure they will get along fine.
Keep an eye on the gerbils for at least a week. Be sure to get a separate cage just in case they do fight. If they fight badly, do not introduce them again and permanently separate them. I had 8 gerbils and alot of them didn't get along with each other(they were from the same liter).
If they do get along with each other, you can put them in the same cage. Be sure to have alot of extra things, like extra food bowls, etc. Just so they won't fight or anything. Also, check your gerbils DAILY. Check their fur, skin, etc. to make sure none of the gerbils don't have any cuts or anything. Hope this helps .