With DITA version 1.3 and specializations you should be able to apply conditions to parts of maps. You can achieve some of this effect in DITA version 1.1 or 1.2 with PIs that constrain the scope of ditaval conditions; and as a bonus, you can reuse topics in multiple places in the same document.
Note: Ordinarily, DITA PIs should be used only for filterable events; see §38.1.3 Deciding when to use PI markers. Including or omitting the PIs described in this section would affect content, not just presentation, and therefore should be considered a workaround. To preserve interoperability, use them only until the DITA standard includes an architectural feature to address the need for filtering within maps.
§9.6.1 Understanding the advantages of filtering in maps
§9.6.2 Designating map sections as named branches
§9.6.3 Reusing the same topics with different conditions
§9.6.4 Directing a cross reference to the correct branch
§9.6.5 Directing a content reference to the correct branch