So, looks like no one knows. Sad, that is...
For the problem needed to solve, I've just found other condition that would do. However, if some other problem arises with same symptoms and no appropriate condition to use right away - I'd be screwed ))
These common logic expressions in condition blocks are joined via AND logical operator in Notrium. Many conditions have a negated version of themselves. So, a simple use of them looks like
AND ( ~Cj ) where ~Cj is some condition and is either Cj or NOT(Cj)
That's great but we lack the OR logical operator for (AND, OR, NOT) system.
Also, the (AND, XOR, 1) system comprises a functionally complete system of logical functions, but it's not very natural for people to think that way, it's a bit harder...
So this type of problems (as I see for now) could be solved in 2 ways:
1) complete logical calculation in bars, using some new bar like min = 0, max = 1
2) if-then-else simulation via script calls also needs some boolean bar to store current state
The drawbacks of both are using one more bar, besides, if the condition check is nested, you'll need one more bar for each level of this hierarchy...
If someone has something to add to these two ways, please tell.