I have two plugins, MyA and MyB (with masters A & B respectively) .

A contains B, so I want to create a MyAB (containing all of A & B ).

With Tes4Gecko's Merge Plugins MyAB will have A & B as masters, when I want just A.

EDIT: to remove incorrect smiley.

with a bit more work you can probably do it with Tes4edit if the formids are the same.
(and I hate the b and ) being changed into some weirdo face... only one that really annoys me)
Pacific Morrowind

Assuming all the Form IDs referenced by MyB in B are identical to the corresponding items in A, use Wrye Bash to change the master of MyB to A. Then merge MyA with MyB to create MyAB with only A as master.
But if the Form IDs don't match, you'll need to use TES4Edit to fiddle things around before merging.

And if they're not?


Better now?

then its quite a bit more work... and potentially confusing to yourself and the program.
Pacific Morrowind