You have implemented three different features of a program in three different local topic branches.
HEAD ---- B - feature-b
| /
pick-your-features - Z <--- A - feature-a
\
---- C1 <--- C2 - feature-c
You want to have all these features as single commits in pick-your-featuers branch.
HEAD
|
pick-your-features
|
Z <--- A <--- B <--- C