Can a vcenter server run within a another vcenter ?

Can we run a vcenter server within another vcenter ?

This would be temporary.

We want to eliminate one of two vcenters (that are in linked mode).  They are both 5.1 running in linked mode.

I was thinking we can move the esxi hosts (4.1)  from one vcenter  to the other other. One of the esxi hosts has a 5.1 vcenter server and vcenter DB server running on it. Once all the esxi hosts are in the same vcenter, we can shut down the vcenter we no longer need.

Thanks in advance for your response.

Best Regards

Tom