Can Visio enforce subroutine calls in a flowchart?

[LurfysMa]

Is there some way to define a subroutine call so that Visio will check
that the subroutine exists?

I would like to create a flowchart for a moderately complex program.
The flowcharts will all be in a single Visio document but spread over
15-20 pages. I would like to be able to create subroutine calls and
have Visio tell me what page that subroutine is on or if it doesn't
exist.

Something like the off-page connector might work, but it's the wrong
shape, it's really designed as a GoTo rather than a Call, and it
requires that I define the other end imemdiately.

I would like something that looks like the Predefined Process shape
and will allow me to define the other end later. In the meantime, it
will show wome indication that it is undefined.

I can't find anything about subroutines in the help.

Thanks

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