Hello there, KA117.
The option to link bills to checks one time is unavailable. Rest assured, I'll share this with our engineers, and it may be added as one of our future updates.
In the meantime, we'll have to manually link bills to checks.
I have an article here that has the detailed steps to do it: Link the check to the bill.
I'm just a post-away if there's anything that I can help.