Unreal engine 4 blue print merge tool

Hi all,
I’m using git as my version control tool. Now, I have a blueprint that needs to solve conflicts. I opened unreal engine’s merge tool but I can not do anything but accept either source or target. But I want to accept some functions of source and some functions of target, or accept some modification of one function of source and accept the other modification of target. How to do that?
I searched in the forum but can’t find any solution.