Issue with configurting multiple camers and triggers and recording

[Bahia]

So I have the following configuration...

Main Door Camera and Side Garden Camera. I had it configured so if Main Door Camera is triggered from motion, Both Main Door and Side Garden Cameras start recording. This is fine. The issue is this :-

I have configured Side Garden camera to use IFTTT. If motion is detected it will set of an IFTTT event to trigger a 3rd part siren. However, if it is already recording from the Front Door motion, the Side Garden motion will not be triggered.

So imagine this scenario that I need to cover. A mailman, myself, or other legitimate person arrives to my Front Door no IFTTT is triggered but it starts to record. They either deactivate the system, or deliver the parcel and leave. However, if it is a thief casing my property, they now walk down the side garden to check for open windows etc (which is what thieves do... they check for ease of entry, before trying to bust a door down)... because this camera is already recording, it wont trigger motion. Major issue here!! Yes I have video of them (FYI the reason for recording on this camera based on motion of Main Door is to compensate for the lag it takes to record on the camera), but no idea if they are wandering where they shouldn't and trip the third party siren.

There are many such issues with this system.... like lack of an external siren!!!  You guys need to think more like a thief to deliver a suitable product.