You can’t merge your OANDA Prop Trader accounts with an OANDA Global Markets account.
However, if you successfully complete multiple OANDA Prop Challenges, the virtual capital will be merged in a single account up to a maximum of $500,000. If you complete a Challenge that would result in the virtual capital allocation being greater than $500,000, the capital will not be merged into or allocated to a virtual account until such time as you no longer have an active allocation, and a new virtual allocation will be created.
Please note, only accounts with the same profit share percentage can be merged.