At this time, CustomMade does not offer a feature that supports customers accepting proposals from two different makers for the same project.
If you would like to work with more than one maker on a single project, you will need to submit a private project request to the second maker. Here's how it would work:
1. Submit your project and accept a proposal from maker #1.
2. Submit a private project request to maker #2. Learn how to start a private project >>
3. Accept a proposal from maker #2.
4. You now have two projects with two makers, both of whom are working on the same job.