No, you can't.
At this time, representing other artists and producers on That Pitch is strictly forbidden. Agencies, sync agents, reps, etc are currently not allowed to sign up for That Pitch. If you are found to be representing work(s) you have not personally created (and own 100% of), you will be swiftly removed from the platform without refund. All work(s) must have a single sign off contractually for any licensing agreement. This is to protect you. Civil suits can (and do) occur in licensing. That Pitch is not liable for any material you upload, you are.
While it sounds harsh, please know that this policy is truly for your own protection.
We simply don't want you to get sued, lol. 😄.
IMPORTANT: There is a grey territory with collabing. If you are candidly collabing with a friend on a track in the studio, and you both agree that you own 100% of the work(s) from a legal perspective - and sign off as such as the full owner of the material, then legally - that's fine. But just know, you are entirely liable. Once you are paid for any placement, it is entirely up to you to divvy up the money however you see fit "off the record". Whichever agreement you have with that friend is between you both - not That Pitch. Legally, you would be liable for any civil suit that could occur in the future. And legally, you would be paid 100% of the payment in perpetuity, not your collaborating friend. All payments and royalties go to you. There is no workaround for this.