How to distribute the load on a directory in Bitrix?

Question

1C-Bitrix

There is 1C.
From it there are unloadings on 5 sites.
All brands are uploaded to one site (to Bitrix), to the other four, only one brand each (self-writing site).

Now everything is being transferred to Bitrix, under one core, multisite.

How best to distribute the load.
1. make one catalog for all sites and filter by brands
2. make each site its own catalog

Taking into account the exchange of orders, goods, balances, and so on.