Let's say someone is a Torah reader. The weekly Torah portion is Va'etchanan, which contains the first pargraph of Kri'at Shema.
He arrives in shul exactly at the time when he must start to read the Torah for the congregation. He knows that at his reading pace, he will reach the section starting with the verses of Shema Yisra'el (Deut. 6) very close to the ending time of Kri'at Shema.
Can he fulfill the mitzvah of having read the morning Shema while he is reading the Torah portion for the congregation assuming he has the proper kavana (intent) to do this? Is there a rule that one cannot fulfill two mizvot simultaneously, and would this rule apply, or not apply, here?