Add option to existing MT4 Expert Advisor

I want to trade already existing EA on multiple pairs, but only xx pairs at any given time. However, if I set up EA on all pairs I may have too many orders on hand that may cause over trading for the size of the account. In other hand, if I only select couple of pairs, those selected pairs may not trade for several days due to no trade signal. So, I would like EA to scan signal among multiple pairs’ and automatically initiate trade for maxim xx pairs. Example: MaxNumOfPairsTrade = 3 (variable) Let’s say I want to trade 3 pairs max at any given time using an EA. I want EA to scan xx pairs. (example: xx pairs can be --> EURUSD, GBPUSD, USDJPY, USDCHF,AUDUSD, NZDUSD,EURJPY, GBPJPY . Among those 8 pairs, EURUSD , USDCHF & EURJPY got signal based on logic written in the EA and EA place orders on these 3 pairs. Since MaxNumOfPairsTrade is set to 3, EA will not initiate any other trade until one already open trade is closed. So, EA is always looking for trade signal opportunity by scanning xx pairs but only initiate trade on MaxNumOfPairsTrade. settings.