All email services now have the ability to add secondary accounts using pop/imap import and smtp sending. Doing it this way you still get the spam filtering these services offer and when email is imported it does not mark the source server as spam, only the true spam senders or spam content, This is the ideal way to consolidate addresses now instead of using forwarders and it keeps your domains and our ips out of blacklists. 

We understand you cannot control who sends you spam and we do take stringent measures to keep spam to a minimum but spammers find new ways to evade protections everyday and it is impossible to stop it all. We do offer extended spam filtering via a third party which filters your email before it even gets to our servers which is ideal if you do not use other services as your primary email. If you are interested in this service, please contact sales. 

To get started on email import you just need to create an email account in your control panel and then use those details to import into other providers. Make sure you delete the forwarder first to prevent conflicts and redundancy. 

Helpful links

Check emails from other accounts using Gmail

How to add any POP3 Email Account to Hotmail