Zoho CRM Custom Module Integration

We have Zoho CRM set up using the standard Leads, Contacts, Accounts, Deals, Tasks, and a few other modules. We are largely using custom modules AccountLocations (this is for the primary location which would typically be under Accounts, but that is not how our system was set up and it covers many locations an account may already have) which each Location should be associated with one Account and can have many Contacts, Community Events, which can be associated with one primary account and then we would like it to be able to associated with multiple AccountLocations and contacts, MH Terms, which connects mental health conditions to contacts and Accounts/Account Locations identifying what types of mental health conditions someone works with. This is the same for MH Offerings and Treatments. We have also created a new custom module called Market, which is supposed to indicate the markets served by each contact, account, or location. I need advice on how to set these all up without using the Multi-Select Lookup Fields because Zoho has given me 5 but all of these modules need to link together and I hope to have many more custom modules in the future. We need a solid system to link this all together.