You want to have a wallet in which transactions can be made if they are signed by person A and one of B, C and D. Is this what you are trying to achieve?
If so, you can create a 4 of 6 multi-signature wallet in which the keys are A1, A2, A3, B, C and D. (A1, A2 and A3 are all owned by one person.)
I'm not familiar with multisig wallet, how does it work? Do you have to manually input each key? If you lose one of the key, will the wallet be unusable? Can you recommend me some of them, I'm ecstatic to try one out to explore it, seems kind of cool, imagine creating a treasure hunt with this kind of thing if what I'm thinking how it works is correct.