Hi Trong,
Both of these options have their advantages and disadvantages.
If you split the accounts, you have the ability to brand specifically to each market. That's a big advantage of selling to a primary market because it allows you to target it with that very specific branding. What you then miss out on is a secondry market, that is buyers that will only buy what they came for and then leave.
So it's a very effective format for hitting a primary market, but there is low to no secondry market sales (unless your genre is quite varied in range)
The advantages of selling through one account is that you open yourself up to a large secondry market, but you can't be primary target specific because you are covering too many genres to narrow the branding focus. So now your branding and marketing has to be far more flexible to cover a much wider market.
So how do you get the best of both worlds?
Well I think you can do that with either option. Let's say you choose to sell through one account, a variety store is what you have in essence. So you have to think like a bricks and mortar store would in design and marketing. Keep your navigation sharp and always cross market your listings by promting customers with deals on other products in your store to create secondry marketing opportunities.
Branding is super important now, you need to build a brand that speaks to everyone, at least to everyone in your wide market.
If you choose to go with split accounts, then cross marketing your other accounts is super important to try and hit that secondry market. For example, just because you are selling hardware on one account, doesn't mean you shouldn't be advertising another account's products, for example stereo equipment.
Sure, the customer will have gone to your account to buy hardware, that's not in dispute, but that doesn't mean that they aren't automtaically interested in stereo equipment. So cross marketing your accounts can bring your other accounts, that weren't the primary sales point, into play with secondry sales opportunities if your customers know they are there.
So two options, both need attention is slightly different areas to one another, but both are very workable if you are smart with how you set them up and market them effectively :)
Cheers