I think this can be done w/ Field Collapsing
http://wiki.apache.org/solr/FieldCollapsing#Quick_Start
Their example is similar except instead of types they are splitting the price into ranges:
We can find the top documents that also match arbitrary queries with the group.query command (much like facet.query). For example, we could use this to find the top 3 documents with in different price ranges:
http://localhost:8983/solr/select?wt=json&indent=true&fl=name,price&q=memory&group=true&group.query=price:[0+TO+99.99]&group.query=price:[100+TO+*]&group.limit=3
In your case group.limit=10.