Basic Midi Question DT DN DeepMind

I own a DT, DN, and a DeepMind 12d that I’d like to share the clock sync from the DT. I managed that alright by wiring:

DT MIDI OUT>>DN MIDI IN>>
DN MIDI THRU>>DEEPMIND MIDI IN>>
DEEPMIND MIDI THRU>>ZOIA MIDI IN

So, all good so far for the clock sync. Now I want to be able to use my Arturia KeyStep as my keys for the DN and the DeepMind. Obviously, I can’t go from the KeySteps MIDI OUT>> to either of the MIDI IN’s on the DN or DeepMind since they’re being used for the clock sync. So, do I just need a MIDI splitter cable and move it between the synth I want to control? Also, what if I want to control both synths at the same time? Is that what a MIDI THRU box is for?

Ps, if you’re thinking “is this guy a total n00b?” Yes. Yes I am. Purchased my first piece of hardware, ever, three months ago (the DT) at age 43. Then two months ago, I picked up his twin sister the DN. Last, I bought the DeepMind 12d last month. Still trying to figure out midi, mixing, fx, the whole thing. I couldn’t be happier though. I’m late to the game but never want to go back to the pre-hardware life again! I’m a lifer and the GAS is strong with this one.

Thank you in advance for your help and any tips you feel are relevant.

PSS I did search the forums first for an answer, but didn’t see my issue.

Dt out to keystep in, keystep out to Dn in, Dn out to deepmind in.