How do I load an ical into a group calendar?

I have a BBM Group set up for my wife, eldest son, and I to manage who needs to be where and when and with what vehicle.

I want to add a couple of ical calendar's to the bbm group so we all have them and we know when the two youngest kids have games and practices, etc.

I can add them as a new account on my phone but then the other two can't see them.

Is there a solution other than manually adding them?

Thanks.

I only see a manual add for the group calendar.
Why don't you provide everyone with the same ical file and have them subscribe to it like i do for my sports team calendar...then they'd all have the same calendar.