In standard Freshdesk a company is linked to one or more contacts. It is the company to which that contact belongs. The contact is determined when creating a ticket, so any link with the company is made at the same time. So:
Are you trying to have contacts linked to more than one company
Are you using Company in a different sense. If so, is it a field in the ticket. If that is the case it is easy to set up an automation rule.
If you define what a company is in your question, and where this is registered I might be able to help.
2 days ago
I agree with Mark - your question isn't 100% clear. Do you mean "groups" instead of "companies"?
If yes than you can go to "Automations > Ticket Creation > New Rule" and do something like:
If you did mean company, like if you get an email from an unknown requester and don't know which company they work with then unfortunately I don't think there is any way to automatically associate it to a company based on the content.