Regarding Data Trees - Inserting items at a specific position in a list of branches

I have a list of items as below broken into branches. Let's just say its points along a set of curves.

[{a,b,c...}, {a,b,c...}, {a,b,c...}, {a,b,c...}, {a,b,c...}]

I than have another set of points as follows
[x1, x2, x3, x4, x5]

How do I make it as 

[{x1, a, b,c...},{x2, a, b,c...},{x3, a, b,c...}...etc]