Your use is not grammatical because the sentence begins with a gerund (guiding) which is the subject of the verb "is", so that the clause introduced by "so as to ensure" is not attached to anything.

so as to = because we want to or because the intention is

We guide students so as to ensure that they get a big picture....

(slightly less wordy version): We guide students to ensure that they get a big picture....

This doesn't quite work:

Guiding ... is a designated role for the government {because we want to} ensure....

But this formulation would work:

We designate for the government the role of guiding students down the right career path because we want to ensure they get....

We designate for the government the role of guiding students down the right career path so as to ensure they get....

Your use is not grammatical because the sentence begins with a gerund (guiding) which is the subject of the verb "is", so that the clause introduced by "so as to ensure" is not attached to anything.

so as to = because we want to or because the intention is

We guide students so as to ensure that they get a big picture....

(slightly less wordy version): We guide students to ensure that they get a big picture....

This doesn't quite work:

*Guiding ... is a designated role for the government {because we want to} ensure....*
*Guiding ... is a designated role for the government {so as to} ensure....*

But this formulation would work:

We designate for the government the role of guiding students down the right career path because we want to ensure they get....

We designate for the government the role of guiding students down the right career path so as to ensure they get....