Would it be possible to set the data limit for a phone online versus using the phone?

[Royel]

I have 6 phones and would like to be able to limit the data usage from myverizon web page.

[Snn5]

You will need Family Base from Verizon to do this from the account level, otherwise each user will have to be trusted to use only what they are allotted.  You can also change the data use monitor in the phone under Data Usage settings to turn off data at a specified amount.