You are in a subfield of physics that is financially strapped. You are asked to do a technical review of an experiment which is not directly the same as one you have proposed, but if it is not funded, yours is likely to be (or vice-versa).
Responsible Conduct of Research and Participation Conflict of Interest Discussion
Further Discussions
Other ethics study topics also discuss conflicts of interests.
Refereeing (Publications)
Peer Review (Publications)
Conflict of Interest (Research)