If your monitors are running Photoshop, and you want to preview what your images will look like when printed by your G7 printer, have them give you a profile of their press (or their proofing system) and you would view your images through the soft proofing function of Photoshop. (View > Proof Setup > Custom)
The Gracol specs lie within the color gamut of the average monitor except for some saturated greens and cyans. Usually we let the monitor profile and Photoshop do their job and bring the colors into the gamut of the monitor the best they can. This is typically good enough to get a close match, if you keep in mind that some greens and cyans might be more saturated on print than on screen.
The Kelvin value for your monitors should be set to whatever white point will give you a close match to your 5000K viewing environment. You will want the white of your light box (for example) to match the white of your display in brightness and color temperature.
I guess it’s not so much that you’re supposed to adjust your displays to look like G7… but rather, the way we do things is to get our displays properly color managed, so they are giving us correct color - and then soft proof using a good printer profile, so Photoshop can do what it’s supposed to do - adjust the image through the printer profile so we’re seeing it the way the printer will change it.
There’s a lot more that can be said depending on your needs. Are you calibrating your monitors? Do you need hard proofs? Your iMacs might be too bright for your viewing environment. You might want a wide gamut monitor to view more of the Gracol gamut?