For the v4.3 EA’s just divide the recommended lot size according to you account size by 3. For example, for a 10K account the lot size is 0.33 lots. This will limit your risk if you are trading just one EA to 1%. So if you are trading 3 EA’s and you want to limit your account risk to 1% then you must divide evenly between the 3 EA’s. So each EA would then need to use 0.11 lots.
For V5 use the set files to determine the lot size for each of the three EA’s. Then divide each EA’s lot size by 3.