Bake Several RBD Objects into single NLA Strip

I have a rigid body dynamics animation of some letters falling that I have to retime as a whole.
I have already baked them but would like the possibility to put them in the NLA editor as a whole word rather than individual letters.
What is the best strategy to pull this off and reuse the animation I have already baked and tweaked?

There might be a better way-- it seems like there’s now more multi-object support in the NLA in recent versions, but I’m not sure and haven’t investigated deeply-- but personally, the way I keep actions and multi-object stuff organized is to use an armature.

One bone for each letter. Copy transforms from the letters. Bake action. Parent letters to the bones and delete keyframes on the letters. Now it’s just one action, in charge of the whole word via an armature.

I see… would the individual bones need to be parented to a single master bone to appear as one action?

No. They’re all in a container, the armature object, which is what holds the action. But for convenience, you might consider doing that anyways.

Thanks appreciate the help