Is there an Attach Option in Blender for Splines? Update 2
I achieved the needed model by using the Knife Projection tool. Thanks to all the suggestions.

I am trying to create an object using Splines and would like to sort of "Attach" other splines and do some boolean operations on them before extruding.

As an example in the picture below there are multiple spline shapes,a ractangular one, a set of circles, and another rectangle.

I am trying to attach (using the word attach here referring to a similar concept in 3ds MAX) all of them together and then subtract the inner circles and the rectangle.



I can not find a way to do that, can someone point me in the right direction please.

Update 1
I followed the idea of going with the Join as suggested by the answer and somehow that does not work as desired.
Let me explain. Here is a simple image that I am trying to create.



Created the desired number of individual spline polygons and placed them like so:


And after the Join:



Notice the extrusions/extra faces below the tall rectangles?
Any idea how I can make it not take the lower part of the door way?

Thanks &amp; Regards.
The right term in Blender is Join. Select all your curves, then Object/Join.

In the Curve panel, make sure your curve is set to "2D", so the inner shapes can be subtracted from the outer shape.