Amazon SES possible to use for company emails

Yes, this is possible. Here is the documentation link for configuring any email client to use an AWS SES SMTP interface for sending emails.

Excerpt from AWS SES FAQ (please follow link for the latest details):

Q: Is there a limit on the size of emails Amazon SES can deliver?

Amazon SES accepts email messages up to 10 MB in size. This includes any images and attachments that are part of the message.

Q: Is there a limit on the number of recipients I can specify in a single email message?

You can specify a maximum of 50 recipients for every message you send using Amazon SES. This limit includes all addresses on the "To:," "CC:," and "BCC:" fields. If you need to send an email message to more than 50 recipients, then you have to split your recipient list into groups of 50 recipients or less, and send separate messages to each group.

Q: Are there any limits on how many emails I can send?

Every Amazon SES account has its own set of sending limits. These limits are:

Sending quota—the maximum number of recipients that you can send email to in a 24-hour period. Maximum send rate—the maximum number of recipients that you can send email per second. Sending limits are based on recipients rather than on messages. You can check your sending limits at any time by using the Amazon SES console.

Note: If we determine that the email you send is of poor or questionable quality (for example, if it has high bounce or complaint rates, or if it contains unsolicited or malicious content), we reserve the right to pause your ability to send email.

However receiving email from SES is a different story. The SES service relies heavily on AWS S3 service for storing your emails and optionally on the AWS SNS service for delivering receipt notices of inbound emails. See HERE for the possible configurations.

If you wanted to use Horde for both sending and receiving, you would need to write some software that pushes your emails from S3 down into your inbox. Based on personal experience, I find that the IMAPv4 protocol works well for injecting messages into an inbox.

A suggested architecture would rely on an AWS Lambda function that is triggered by an AWS SQS Message. If you configure SES to produce an SNS notification and subscribe an SQS queue to the SNS notification topic. For each emitted event, the lambda code would unwrap the SQS message, decode the SNS notification therein and then extract the email S3 path information from the SNS notification message. Finally, after pulling down the emails bytes from S3, push the message to your prefered IMAPv4 inbox folder.