Don't double up your risk by trading the pairs that tend to move in the same direction or opposite to each other.
Here is some major currency pairs and thier crosses. If you get a strong euro cross trade setups just trade one euro cross, Don't trade all of them then you will end up winning all the trades or losing all the trades, reason behind that euro crosses move based on EUR/USD most of the time (Just compare all euro crosses with EUR/USD pair to get an idea). If euro goes down against dollar then euro weakening against all other currencies. So just find a strong trade setup @ one cross pair and ride the whole trend with the help of one dollar based currency pair. I hope this table will help you to minimize your risk.
Have a great trading week!