In this paper, we describe and implement compiler extension for a parallel computer language called Associative Computing (ASC) language to support multiple instruction streams in a Multiple Associative Computing (MASC) model using manager-worker paradigm. A user directed MASC directive is used to enable concurrent executions of the THEN part and the ELSE part in a parallel IF- THEN-ELSE statement by using two different worker- instruction streams. For most applications, this technique should substantially improves the performance of the system over its performance using only one instruction stream; moreover it is more effective than using multiple instruction streams to execute every parallel IF-THEN-ELSE statements found in a program. When the overhead outweighs the benefit gained from using multiple instruction streams, a user can choose to use only one instruction stream to execute the IF-THEN-ELSE statement. While not explicitly covered here, parallel CASE statements can be handled similarly.