WP Travel Group Discount is an addon to WP Travel which allows you to set the discount on the basis of user’s group.
In your particular case, first four pricing options single, double, triple and quadruple can be defined with the multiple pricing option and the prices to different options can be defined with the WP Travel Group Discount addon.
Also, for the case of junior and children , you can define the prices for this group with the group discount addon as well.
However, the checkout process for the first four and last two categories have to be carried out separately because the feature of multiple checkout is not present in the plugin as for now. If your requirement is to carry out the checkout process for all the groups with a single cart, you need to hire our professional developer as, the feature requires modification in the core plugin file.