Gaps and Islands analysis in Cognos

Question

Using Cognos Analytics 11.1.7IF9, but asking about Cognos Analytics/Business Intelligence report development in general.

Continuation of my SQL question regarding gaps and islands.

For performance reasons, I have created SQL code using CTEs and have added this to SQL objects that feed queries. Each of these statements uses a different data source. I want to avoid asking the database administrators to create something on a database server for me. I want to do the remaining query work in Cognos.

The results of my SQL statements is a query generated by UNIONing these together into a query named "combined".

In Cognos.
Is there a way to use minimum or maximum with additional parameters?
Can I perform LEAD or LAG functionality other than joining a query to itself on row-number = row-number - 1?

Below is SQL code that works. Can this be done in Cognos?

with
ranges as (
    select SRID
    , MIN(ARMBegin) OVER (PARTITION BY SRID ORDER BY ARMBegin, ARMEnd ROWS BETWEEN 0 FOLLOWING AND UNBOUNDED FOLLOWING) as WindowStart
    , MAX(ARMEnd) OVER (PARTITION BY SRID ORDER BY ARMBegin, ARMEnd ROWS BETWEEN UNBOUNDED PRECEDING AND 0 PRECEDING) as WindowEnd
    from #combined f
),
groups as (
    SELECT SRID
    , WindowStart
    , WindowEnd
    , LAG(WindowStart,1) OVER (ORDER BY SRID, WindowStart, WindowEnd) AS PreviousStart
    , LAG(WindowEnd,1) OVER (ORDER BY SRID, WindowStart, WindowEnd) AS PreviousEnd
    FROM ranges
),
islands as (
    SELECT SRID
    , WindowStart
    , WindowEnd
    , CASE WHEN PreviousEnd >= WindowStart THEN 0 ELSE 1 END AS IslandStartInd
    , SUM(CASE WHEN PreviousEnd >= WindowStart THEN 0 ELSE 1 END) OVER (ORDER BY SRID, WindowStart, WindowEnd) AS IslandId
    FROM groups
)

select SRID
, min(WindowStart) as IslandStart
, max(WindowEnd) as IslandEnd
from islands
group by SRID
, IslandId
order by 1, 2, 3