Storage optimization across the Datastore

Hi,

I have created two datastore sizing 500 GB each.

My question that;

1. In one of the datstore I need to extend the storage say datstore1.Kept two VM each from esxi host in the cluster.

2. The datastroe 2 ius underutilized.Can datstore1 borrow space from that?If yes how this needs to be done.

3. If I create antoher datastore3,can I add this storage to datstore1?Do I need to extend volume or something else here.

What is the best way to achieve that.

Regards,

Sushil