Many Solo 401k plans for one tax-id

[Dev S.]

My S-Corp has myself and my spouse as employees. We both have chosen to contribute to individual 401k plan but through different brokerage firms to take advantage of different plan provisions. Can we both have different accounts through different providers under same tax-id/EIN? I have read through forums that there can be different accounts for each participant but I am unable to find any documentation where it mentions that each participant can have a separate plan provider.