Getting children-pages from two or more sections-pages

[flexocms]

We need to add method to FrontPage for getting childrens of two or more section-pages.

Problem were explain here: https://groups.google.com/d/msg/flexo-manage-content/HrKAwGVg2QQ/7hY2F7XWMY8J

I write partly snippet-solution here: https://groups.google.com/d/msg/flexo-manage-content/HrKAwGVg2QQ/moRnc5YBHUsJ

Need feedback for this issue.