Digikam as archive of historical photos

Hello,

we want to used digikam for an archive of historical photos. For these 
an exact date can seldomly be given, only a time range can be guessed. 
It would be great, if this range A) could be specified in a compatible 
way and B) could be taken into account in searches. For example when 
searching for photos between 1950 and 1959 we would like to find those 
with a time range of 1945-1955 and those with 1958-1962. Has anybody a 
solution for this?