PowerShell Get all users in a SP Group from a subsite

Is it possible to get all users in a subsite. I found a script online but I keep getting the URL/ID cannot be found. The same command essentially works for the site collection but it doesn't work on the subsite.

Get-SPSite http://server/sites/yoursite |
 Select -ExpandProperty RootWeb |
 Select -ExpandProperty Groups |
 Where {$_.Name -EQ "your group name here"} |
 Select -ExpandProperty Users |
 Select Name, Email

Can someone put me in the right direction? Thank you.