Implement two stores on the OpenCart system

There is a working wholesale online shoe store on opencard and a warehouse program My Warehouse (without integration with the store)
We want to launch in addition to wholesale 2 more directions - retail and dropshipping.
All three destinations will have different prices, and different addresses, respectively, you need to make either 2 more sites or make a cartoon store.
If we make separate sites, then you need to make it so that you can manage products through 1 site (and not add / remove 1 product on all 3 sites manually)
For dropshipping, it should be possible to create new sites if necessary and connect our products and balances to them.

Task:
1. You need to figure out how to implement such a system, maybe switch to another CMS
2. Make integration of goods and balances with the My Warehouse system
3. Choose 1 general template design for 3 sites (or one) and put it
4. Make an integration with the Unisender mailing service (there should be a distribution of categories of users of the retail, wholesale and drop site in 3 different databases)


Also, for a better understanding of the functions of the sites:
Retail site functionality: Regular online store, orders from which fall to the mail and to My Warehouse, retail prices
Functionality of the site by wholesale: The site has widgets for parsers of goods (for example, turboparser), registration on the site is mandatory for ordering, orders fall on the mail and in My Warehouse, wholesale prices, in your personal account you need to synchronize the status of orders with My Warehouse
Functionality for dropshipping: Also an online store, orders from which fall to the mail and to My Warehouse, but here we need to finalize the personal account so that our partners can track the status of orders and money payments on them, prices for dropshipping