Selecting transactions with two accounts

[Ben Pracht]

It's tax time again in the US.  I'm trying to figure out how much money 
in cash my insurance
companies have reimbursed me for medical expenses.  I've set it up so 
that reimbursements count
as income under the account Income.Healthcare Reimbursements, and the 
cash account is
Assets.current.Cash On Hand.

I'd like to find all the transactions of the form:
Debit to Assets.current.Cash On Hand
Credit to Income.Healthcare Reimbursements

I've tried to select the two accounts, but the search results always 
come back empty, even though I can find a few by hand.  What gives?  I'd 
settle for knowing which transactions involved both accounts, without 
regard to which was debited and which was credited.

Thanks,
Ben