Can I edit an adjustment layer that affects multiple sequences?

As Kevin said, you can apply the lumetri effect as a source effect to your adjustment layer. After that, you can use this adjustment layer wherever you want in your project. The tricky part using this technique is that you can't see the adjustments directly while adjusting lumetri effect in the source tab of the effect controls panel.

In your case, if you have one adjustment layer in your project panel that you used in all the sequences then do the following:

In one of your sequences add 2nd lumetri color to your adjustment layer, do your adjustments, cut the 2nd lumetri effect, go to the "Source" tab in the effect controls panel and paste.

Hi @ndelcastillo,

Thanks for writing in such an excellent question. I did an experiment to try and replicate what you want to do and was able to succeed. 

I created a Production with multiple projects and different sequences. One of the projects is called "VFX," where I keep all my adjustment layers. I created a new adjustment layer and added a Lumetri Color effect to the adjustment layer in the Source side of the Effect Controls panel. I took down the Saturation and adjusted curves. I applied the adjustment layer to two different sequences in two different projects. Making adjustments to the adjustment layer in the VFX project does act like a "master" effect that has the potential of affecting multiple adjustment layers in various sequences in projects related to the Production. 

Please try this and see if you can add it to your workfow; If you are having trouble or wish to share any other findings, please return and share those. I hope the advice helps you.

Thanks,
Kevin