Update quantity to set multiple of account group trade

It would be great if the quantity values shown in the DOM and charts automatically update to reflect the quantity associated with the group.

For example, if I have a group setup with 7 accounts with 1 qty each (therefore a total of 7 quantity), then after I select the group to trade with and the account associated with that group the quantity selector would update to be in multiples of 7 (or whatever the quantity is associated to the group)