Is There a way to merge two nodes in one?

This is one of the characteristics of hierarchical trees. It is common for some information to be required in two places at once. Solutions include:

1. Redesigning the tree to avoid this split, so that common information is higher up in the tree
2. Creating a common parent for the A-Delta and C types, then adding a bracket boundary with a callout on it to continue with common information
3. Using a relationship to merge the flow of information to a common topic

Option 2 works visually but you would not be able to transform it to a linear document. Option 3 would still permit transformation to a linear document with a "See also" link following the relationship.