Apologies—the meaning of the term “splitter” is not apparent. Assumed it’s used to establish taps.
Read the surge-arrester literature carefully: "Wiring Feed-through dual lugs rated 100A maximum continuous line current using #3 AWG conductors"
So, no—it looks like it won't work as claimed unless ‘loop through' is used. [Get it in writing from the TVSS manufacturer if there’s any question of this.]
Think you'll find that a "Kelvin" connection is required to meet their advertised capabilities, and as such, only suitable for a 100-ampere-maximum circuit. Likely too are that separate raceways must be installed for incoming and outgoing conductor bundles; id est, a single-nipple connection to the TVSS containing all conductors is probably verboten if one wants to preserve the published ratings of the device. [Heed manufacturer’s ground-conductor instructions and routing to the letter.]
You may want to install three of the subject devices—two for the 100-amp panels connected in ‘loopthrough,’ and one in a non-looped/tapped arrangement for the 200-mp panel, understanding that the suppressor will not be as effective in this mode.
If the building owner still insists on this particular device then point out the deficiency, get paid, and walk away.
