> 僕らはお互いを電話すれば、お互いをわかりますかな?

- 僕らは is not necessary because it's safely inferred from the context.
- Unlike *call*, 電話する is *not* transitive. The particle you need here is に. Or you can just use お互い without any particle because it also works as an adverb.
- ～ますかな is a very pompous way of asking a question. I hear this only in fiction, typically from noble people and stereotyped elder gentlemen.
- Neutrally saying ～ますか is not a good way to ask a question like this anyway, because you are expecting a positive response. (i.e., You want to say "we do ... don't we?" or "Don't we ...", not simply "Do we ...")
- 分かる is rarely used transitively. Use ～が分かる isntead.
- Try using [～あう][1] here. If you can use this the second お互い is redundant.
- "At all" in a positive sentence can be translated as とにかく, ともかく, 何にせよ, etc.

Fixed version:

> - お互いに電話すれば、お互いが分かるのではないでしょうか。 (still slightly clumsy)
- 何にせよ、お互い電話すれば、わかりあえるのでは？
- 電話で話しあえば、ともかくわかりあえるんじゃない？ (casual)

  [1]: http://www.jgram.org/pages/viewOne.php?tagE=au