They make Y adapters or you could make your own. If you have the 30 amp TT adapters that fit the generator you could use this as is:
https://www.amazon.com/LeisureCords-Adapter-50Amp-Female-Handle/dp/B07B5S9GC4/ref=pb_allspark_dp_session_sims_pao_desktop_3/130-6287419-1614518?pd_rd_w=GIVNY&pf_rd_p=3ac2ce50-9d75-4bd3-868d-72b252a0623c&pf_rd_r=9NYD8R3TD4N39TA0HJA5&pd_rd_r=510ae72c-a379-4280-b4b0-ee3659f9c59f&pd_rd_wg=3ysKF&pd_rd_i=B07B5S9GC4&psc=1You could put together short 10-3 SO cords with L14-30 male twist lock ends and a 14-50R strait blade receptacle in a 1 or 2 gang weather proof bell box. This single gang box is what I'm thinking:
https://www.homedepot.com/p/BELL-1-Gang-Gray-Weatherproof-Box-with-Four-3-4-in-Threaded-Outlets-5330-0/204208015But the ones I've seen are made with the 2 gang bell boxes. Pretty common item with those Honda 7000 generators.
I just run a Eu3000is now, that size is more manageable for me. The EU7000is is a heavy beast.