In Xshippingpro, you can divide all shipping methods up to ten group. Why do you need grouping?  It can be used following cases:

1. You can hide/filter out unwanted shipping method at certain scenario. For example, You have two shipping methods a. Free Shipping when order total is greater than $100 and b. Flat Shipping $20. So whenever a customer purchase products worth more than $100, it will show two shipping methods during checkout which are Free Shipping and Flat Shipping. Since it is bit awkward having free shipping and flat shipping at a same time. So you can hide Flat shipping whenever Free shipping activates. we can hide it using group feature.
2. Merge or combine shipping cost of several shipping methods into one. For example, You want to charge $5 per product for category A and $7 per product for category B. So you have created two shipping methods. One for category A and another for Category B. Whenever customer purchase products from category A and Category B together, you want to sum up the cost. Group option can do that.

It support following group type or mode:

1. Lowest   –  It will show the method which have lowest cost among the group methods
2. Highest  –   It will show the method which have highest cost among the group methods
3. Average –   It will average the cost of the group methods.
4. Sum –   It will sum up the cost of the group methods.

For defining several method as a group, first you will have to navigate in Xshippingpro -> Global setting -> Group Option

Now select Group type from available ten groups.  You can also enter a group name. This group name would appear instead of Method name if that group become activated during checkout. This group name can be combined with original method name and its price as well. For placing list of method names, please put @ and for list of prices # is needed to be placed.

Now you will have to assign your group number to the methods that you need to be linked together under general setting of each method.

Group creation is done!

Finally, it is also possible to make group from the Groups! This is called Group in groups. This group will determine based on Sort Order value defined on general tab of the each method. Shipping method having same sort order value will be placed into same group. Group of groups also can be Lowest, Highest, Average and Sum.

To know more details about top level grouping (Group of methods) and Second level grouping (Group of Groups), please check this