Synchronization of two branches of Mercurian

I sometimes need to "sync" the current (named) branch A with another branch B, i.e. concatenate B to A and then concatenate A to B.

This is how I currently do it in TortoiseHg:

• Update to end A (if needed)
• Right click on B, "Merge with Local ..."
• Update to end B
• Right click on A, "Merge with local ..."
• Update to end A

Is there an easier / faster way to achieve this?