Can you segregate the connection or connections from company B so that all of their traffic is on the Internet side of any firewall or internal routers you are using?
Here is something that may help you to convince management to have company B get their own broadband connection. With a shared connection, if anybody at company B were to get involved in any shady activity, such as illegal file sharing, it would be quite likely that your company could be on the hook for any fines, lawsuits, or worse.
You may also want to check the wording of any contracts you have with your Internet service provider and review their terms of service. They may prohibit sharing the connection with other companies.
Here is something that may help you to convince management to have company B get their own broadband connection. With a shared connection, if anybody at company B were to get involved in any shady activity, such as illegal file sharing, it would be quite likely that your company could be on the hook for any fines, lawsuits, or worse.
You may also want to check the wording of any contracts you have with your Internet service provider and review their terms of service. They may prohibit sharing the connection with other companies.