filtering a record on a record of another talble

Hi Everyone,

I have two relations,
A = Load '' as (cid,msisdn,starttime);
B = Load 'WebLog' as (wid,msisdn,timestamp,timesttampUpper,timestampLower)

(timestampLower = timestamp - 15min )
(timestampupper = timestamp + 15min )

We need to filter all weblog data on misdn(CDR) and (starttime <
timestampUpper and starttime > timestampLower).

I am not sure how to do this.
My attempt below
(C = filter B where msisdn = A::msisdn and (A::startTime < timestampUpper
and A::timestamp > timestampLower)

please guide

Thanks,

Krishna Kalyan