Is anybody using buy limit feature?

Looking at the bracket order implementation in backtrader, I think something is missing.
When I do bracket order with broker (long for example), I have the option to specify buy limit. For example, if close price is $50, I want to buy at $51 but not to exceed $52 and then stop loss is $45 and Take Profit is $60.
I see that stop loss is implemented as sell stop and take a profit is implemented as sell limit which is exactly what broker offer. However, I don't see the limit for buy entry. The reason behind this limit is, I want to catch momentum when equity is going up but if it gaps or goes to high, it is not worth buying it anymore.
Can somebody help me explain how to do this in backtrader if possible?
Thanks

I have read documentation and went over the issues that people had regarding this but still can't find an answer to my question so I am hoping someone can help me out here.
Basically I have strategy that uses multiple data feeds (each feed is for specific equity) and I am creating own indicator.
My understanding is, the output lines of the indicator will be array of lines (Line for each feed or equity). Is my understanding correct?
If so, how do I define lines array inside the indicator? all I am seeing is
lines = ('metric1','metric'2)
If I have multiple feeds then I should have an array of metric1 and metric 2 for each feed, correct?
Size of the array will be the number of the equities I am feeding to my strategy. That number will be known in my strategy and should be passed to indicator at instantiation. ?
Can you somebody help?
Thanks