[Koha] 852's $h and $i into one 952's $o

How do I use MarcEdit's Find/Replace function to move 852's $h and $i subfield data into one 952's $o subfield? If I try to swap $h of 852 to $o of 952 and then do that again for $i of 852 field, I end up creating two $o entries in the 952 field, which I don't think is allowed for call number subfield. Also, I don't have the slightest idea how to use regular expressions to achieve the said task, so I would appreciate it if someone could write it for me, or at least guide me how to write one. regards, Maxwell