Group membership - Add group members to 2 or more different Joomla Groups

We use Membership pro with Events Booking to manage who can register for our events.
We have Family Events, Adult only Events and Childrens Events

We have Family memberships that allow members to book Family events on preferential terms.

One of the family memberships plans we call plan A2C1 (2 adults and 1 child). The person purchasing the membership is allowed to add up to 2 group members in Membership pro.

We have three Joomla user groups A2C1 , A1, C1  who can book In our Event Booking System

Joomla group A2C1 Can book Family Events, A1 can book Adult Events, C1 can book children events

The group owner is allocated to A2C1 and A1 Joomla User Group
When the group owner adds a member The member is allocated to A1 only (via being excluded from A2C1 by the Membership Pro - Group Membership Plugin exclude Group id feature). 

What the group admin can’t do is add the child with Joomla Group C1 they can only be allocated A1.  We ( the admins) then have to go in and manually change this from A1 to C1. 

Is there any way we can automate this or allow the Group admin to add members with different Joomla User Groups